If you can find an RoW at a good price, any day of the week, go for it just because it’s a great transformer. That said, lacks compatibility with some(actually majority) of the newer electricinics. I wouldn’t say it’s the best/most practical for new command, or even newer conventional, standard or o gauge. And, again IMO- not the best for original prewar Standard or O gauge.
Since we’re talking: conventional with prewar and Lionel Classics(which I’m assuming late 80s early 90s Lionel Classics under Mike Wolf), old accessories, new accessories, and new modern Repro tinplate- I’d suggest the following based on running 2 standard gauge loops and one o gauge loop all with new and postwar & prewar accessories. Keep in mind- it’s always better to have MORE power than you need(i.e. if you’re starting and planning on running one train- buy enough power for two). I recommend that all the PW Lionel transformers below be purchased refurbished with a new power chord and clean carbon(or gold) rollers:
1a.) “The Postwar Power Package” Postwar ZW(repaired/refurbished) and a Postwar V(repaired/refurbished)- direction and whistle control and accessories. Can be bad for a good price But, if you’re running let’s say 1 standard gauge and 2 o gauge tinplate plus accessories then the ZW on its own simply wont suffice. With this combo, 8 total outputs with 190-200 for the ZW and about 100 for the type V. You can run 2 trains on the ZW with whistle and direction control and on the type V one train(no direction control besides turning the knob for FNR) plus your accessories.
1b.) “Best modern w/ a PW secondary”-MTH Z-4000 and a PW Lionel type V, Lionel LW, Lionel 1033- IMO the Z-4000 isbest transformer on the market for the price: bells and whistles, direction, volt and amp meters. It’s status, reliability and safety make it more of a modern PW ZW than the current modern ZW-L**Note- the Z-4000 has had almost 20 years to build this reputation, the current Lionel ZW-L is still working its way into the model train world so this may change**. The 4000 could run 2 trains for you and power your accessories. From there, you can keep it “simple” and go with a refurbed 1033(direction and whistle control) to power your last line and a few lights. You could go with a refurb type V which would add a lot more power, run a train(you’d have to get a 167 controller for whistle/reverse, though) and then use it to power accessories as well. The PW Lionel LW is probably the best transformer(in terms of output) to run a single train and power accessories.
1bi.) “Modren electric Protrction & Prime Power Bundle” MTH Z-4000 and a 750 or 1000- Everything I said above regarding the Z-4000 and then with a z-750 or z-1000. Probably the priciest option. The 750 or 1000 will Power a single train and some accessories. All of these transformers offer circuit protection on their own.
2.) “True to Prewar Max Power Package” Postwar Lionel Type Z (repaired/refurbished) & Type V: IMO, prewar tinplate runs best with the early postwar Lionel transformers(specifically the Z and V). I say that from what I’ve read and from experience. Pack a ton of power. I’m a huge fan of the type Z. Unfortunately, these transformers both lack whistle and direction control. Which is why I recommend...
2a.) “True to Prewar MAX Power Package w/ Whistle/Direction Control”- refurbished Z or V and a ZW. The Z and V have higher output than the ZW or KW. ZW would run 2 trains and the Z or V would run one train and accessories.
2ai.) “True to Prewar MODERATE Power Package w/ Whistle/Direction Control”- refurbed Z or and KW. KW can power 2 trains(in your case I’d use it for One O and one standard). Has direction and whistle control. The Z can power 1 or 2 trains(standard & standard, O and O, standard and O) as well as accessories. Again, the Z lacks direction/whistle control so you’d need a 167 whistle controller.
2aii.) “True to Prewar MINIMUM Power Package w/ Whistle/Direction Control”- Lionel refurbed KW and type V. Same as above except the V might have trouble if you’re using it to power 2 trains and accessories. Also would require the 167 controller.
In summary: In a perfect world with the access to necessary funds and realistic goals , if I had a purelyconventional layout with 3 loops( one loop is 18 feet of track. One loop is 14 feet of track, and the other is 12 feet) 1 conventional 90s reproduced standard gauge Locomotive with 4 lighted Passenger Cars , 1 prewar standard gauge freight Locomotive with 6 -8 freights cars , 1 O gauge Locomotive with 4 lighted Passenger cars, had 8-15 street lamps and 6 lighted buildings- I would likely use:
1.) MTH Z-4000(1 for a standard gaug and one of an o gauge), a refurbed Lionel Postwar ZW(one for a standard gauge) AND with EITHER a.) a refurbed Type Z or Type V for accessories and For growth or b.) a Postwar LW for accessories and/or for growth or to power my 3rd loop separately