I build 1/144 scale commercial airliner models, and have been after the elusive TU154 for awhile. However, I prefer injection-moulded kits, so I haven't tried the 1/144 Welsh TU154. I've heard it's an excellent kit, very accurately shaped, with only the fuselage done in vacuuform. The wings, engines and stabiliser are injection-moulded. It includes white metal landing gear and engine details and has decals for both Aeroflot and Balkan Bulgarian Airlines. The Welsh TU154 is an M series with the larger centre intake and larger pod-mounted engines with clamshell thrust reversers.
The 1/200 ANTK/Tupolev TU154 is a B series, with no landing gear, only a stand, and from what kit reviews have posted, has terrible decals. It makes up into a nice model, to hear it told, but if you want landing gear, you'd have to pirate them from a smaller scale 777 kit (I believe one was assembled using Airfix 1/350 777 landing gear).
Lastly, the 1/100 scale VEB/Plastikart TU154 is hard to find. I've built their TU134, and it makes a pretty decent kit, though it is of an early model TU134. I've heard the same of the TU154 - it is an A model. The VEB TU144 is horrid and completely inaccurate; I have one and am not even interested in building it up. The only IL62 I've ever seen is also by VEB/Plastikart, again in 1/100. It builds up into a decent model like the TU134, but it is, again, an early model with a shorter fuselage, nose probe and the smaller Lyulka powerplants used on the prototype.
Look for other 1/144 Russian airliner models from Welsh, and possibly Minicraft, in the near future.