I have bought entirely too many locos recently, almost all from MTH. But MTH seems to be at the top of its game right now, producing some extraordinarily good model locomotives, and they also seem to be reading my mind as to what locos they produce. And I have been a sucker for Warbonnet since age six, when my whole family took the Super Chief to California. So, I could not say no to the ATSF E-8 A-B-A set (20-20355), nor not also order an extra B unit (not here yet), even though I have an excellent A-A Legacy set of E-9s (Union Pacific, 6-39612) with an MTH E-8 B unit that is an extraordinarily good match to the Lionel models, and even though I also rode UP's City of Los angeles a few years later - also to California. Below, I talk about this new MTH E-8 set, and give my impressions of how it compares to the Legacy E9s.
The MTH Premier A-B-A set. It was well packed, had no rust or missing parts, and arrived in perfect condition and ran right out of the box. It looks spectacular (more below). It feels good, too. All three units are heavy and feel substantial. Lights, including the Mars light, are very good. Sound is good - not quite Legacy good, but nearly, and the sound the unit makes on shut down, sort of a woo-woo-wooo-woooo-wooooo-wooooooooo - whew, sound, is both strange and toy-like. Probably not prototypical, but really fun. The units run very well in conventional. Both A units are powered, I think twin motors - anyway both trucks have the outermost two axles powered, the inner is freely-rotating and blind (flange-less). Only one (the forward A unit) has sound.
My experience is that PS2 and early PS3 locos did not run as well (smooth start, good low speed smoothness and control) in conventional as Legacy locos did, but this set is quite nice. The set seems to pull hard although I have not put it to the test. Horn is okay, nothing special. MTH claims in its features description of this set that it has "two smoke units." Of my two A units, only the forward one generated any smoke.
Minor rant: It took 20 minutes (!!!) to set the three-unit set up on the track because of those @#$%%!!! stupid MTH tethers between units. One cable was too short: I had to turn the B unit over and coax another half inch of cable out of the unit slowly. Both cables were stiff and seemed to fight the couplers - cables and couplers did not like to play nice together. Both connectors really did not seem to seat all the way (it looks like that anyway) but seated enough to run). Setting them up and getting the tethers connector, the couplers connected, and all the wheels on the track correctly was a tedious and at times frustrating introduction to an otherwise fine model. It is bothersome enough to hitch these puppies up that it will make me think twice about taking them down and setting them up to run them in the future. Why does MTH still use this approach? Ugh.
Anyway, the A-B-A set runs and functions as expected: which is to say extraordinarily well. Here is a brief video of the A-B-A set making a slow-speed pass, running in conventional at about 10 volts.
A spectacularly beautiful set. I admit I am a sucker for Santa Fe's Warbonnet. No diesel - no locmotive for that matter - ever looked better to me than Warbonnet EMD Es and Fs do. Here, the paint is very glossy and shiny: certainly no real-world at all, but just spectacular on a toy sitting on my layout . . . . Here is the MTH set along with my Legacy E-9s (the B unit with them is an MTH E-8B).
Another view. Wow. I love both . . .
. . . so a third view. I just love these big boys.
But beautiful as the UP E-9s are, the ATSF E-8s are shiny, with a mirror-like metallic finish that is so cool, and shin, shiny red paint with a still-wet gloss to it. The UP set, including the MTH B unit I bought to go along with the Legacy A-A units (which appears to be an identical model, except for paint and finish, to the ATSF B unit), is all in a matte paint finish - no doubt much more true to the real world. But the MTH wins hands down in the wow factor when its sitting on the track. WOW!!!
Both look a bit ridiculous when rounding curves, with a bit of truck stick out that gives them a bent-lip look. The MTCH ATSF loco is going to a 72 inch curve here, the UP is on 60". I can live with this, but it tell you these are models and running on a small layout . . .
Comparison is interesting. Neither loco is a clear winner here. Both have nice metal screens, good looking trucks, good detail as to fans, pipes and "stuff" on the roofs, etc. Notice in the photo above that the MTH (left) does have more detail as to "stuff" attached to the front of the A units front truck than the Lionel model (right). I do not know if this is a modeling omission on Lionel's part or if it reflects different equipment installed on ATSF E-8s versus UP E-9s. Regardless, I likettached "stuff" so I prefer the MTH look here. Looking at the photo below, lthe roofs are equivalent overall in my opinion. The UP units here have snow guards over the intakes, but I don't think ATSF installed those, and otherwise they are very similar.
I did not count rivets to see if those of these models are the correct number as on the real locos, or if the two companies give you the same number or rivets on these locos. There seem to be a sufficient number in both cases! 
I do know that MTH (below right) gives you 32 spokes on the cover of the big fan on the E-8s, while Lionel (left) gives you only 24 spokes on the E-9s. Again, its this a difference in E-8s and E-9s? I don't know. Does it matter to me. No.
Both companies say they have visible fans underneath the fan shrouds. I can see the Lionel fan and its blade, and when I blow on it, it turns. I can tell something is underneath on the MTH - it is not dark below, but the fan is not as easy to see (you can sort of make it out in the photo below) and it does not move when I blow into the fan. No big deal.
We've had threads recently about the windows on the Legacy locos, with this crease or whatever in the windshield (left). The MTH does not have this. On the other hand the Legacy is noticeable more flush than the MTH, where the window looks to be four of five scale inches farther back inside the windshield frame. So neither wins here . . . The Legacy has railings above the windows. I don't know if MTH left them off or maybe ATSf E-8s did have them whereas UP E-9s did . . .
Speaking of flush windows. It can be done right . . . Here is the 3rd Rail ToT E7.
Both MTH and Lionel have doors that open (yawn - a feature with aboslutely no value to me). Moving on now . . .
A final note if MTH is reading this. I much prefer this model's Operational manual (right) to those for the European series (left): when you have 100 or so to store away, it helps if they are compact.
Summary and final comments. Both sets are great. Neither is perfect. The Lionel set has slightly better sound, the MTH slightly better detail, I think. The MTH is better looking, but that is mostly Warbonnet's doing, not MTH's. Both run very well.
But MTH's A-B-A set is the same price ($929.95 list) as Lionel's A-A set was when I bought it, and for that they give you two powered A units - four motors, not just two, for your money. I bought both sets a mild discounts by shopping around, but I paid the same for the MTH A-B-A set as for the Lionel A-A set. A extra B-unit is about $250 of so . . .
So if I could afford just one, I'd go with MTH, Even as much as I dislike those annoying tethers.
. I agree with what you said except for the functional doors, which I think adds class to any locomotive. I very much agree about the PITA tethers, to the point where I don't want any more tethered engines. I only bought my PS3 NYC E8 ABA's because they are beautiful Jade Green. The fact that they have great sounds, smoke, detailing, and are great pullers is icing on the cake! C'mon MTH, lose the tethers already
it looks sooo goooood I just wanna go there and give that engine a big 'ol kiss. But I don't want to smudge the SS finish.
