When the Legacy Mohawk (6-11411) appeared in the catalog a year or so ago, I didn't order - NYC is not my thing, etc., I had two other locos already on pre-order and several from that catalog I was considering. But recent prices made me take another look: at 40% off, this was a great buy. I am more than pleased with it.
As I have come to expect from Lionel steam: it arrived in perfect shape, and everything works as it should. Casting is detailed everywhere I looked. Paint is excellent. All the printing crisp: with a jewler's loop I could read all the complete builders' plate (April 1926) and the smaller Superheater Company plate above it (I tried to get a picture, but no dice . . . ). It has a lot of "separately applied parts," sliding cab roof hatches, etc. - just excellent detail. Numbers and boards and all. Lights are above average, as I'll show below. Sound is average for recent Legacy - which means very, very good! Smokes a bit better than most: puffs nicely but flows just enough at idle.
It is a very handsome locomotive as you can see.
I just love a loco with an intensely industrial technology look - lots of tanks and pipes and equipment. This is one of the best. That's my 4199 Berkshire on the upper track - one of my favorites.
I particularly like the size, which is perfect for me. I have 72" curves so I can run even the biggest Big Boys, etc., but anything bigger than an ATSF Northern looks a bit bizarre on my layout, sticking out on curves - the Berk is maybe the perfect size. This Mountain slots in right between the Berk and the ATSF 3751 in size and will be a near-permanent fixture with the Berk now. Perfect size. Third loco in the picture below (on top) is another favorite runner: a Southern Crescent (really is - repainted). 
I love the lights, they are bright and just well positioned. The green are bright to well diffused inside their little lanterns - they look real.
The cab lighting and cab detail as as good as any I have, and the red lantern lights at the back are really nice looking. 
It is a superb runner, too, although that is not unusual: all recent Legacy steamers seem to run sooooo well. Here is a brief video of it running in conventional - this is the speed I most love to run my trains - just rolling through town.
Eventually, thi will get some paint/relabeling - either ATSF or UP, I have not decided, and will stay on the layout most of the time. Fantastic loco. I actually went back to the Klein website to see if they had another at this price, but all gone . . .
