These are my personal thoughts on some of the trains used in the UK on the National Rail network. These are from the perspective of an able-bodied person who happens to be 6'2" (so if I'm not complaining about the height or legroom or something, it's probably adequate).
Class 158 Express Sprinter (Transport for Wales)
Class 170 Turbostar (CrossCountry)
Class 172 Turbostar (West Midlands Railway)
Class 196 Civity (West Midlands Railway)
- Exceptionally striking and modern looks with a very well-suited livery
- Is whisper quiet inside the cabin, and not exactly very noisy outside
- Squeaky brakes
- Has the typical rough CAF ride quality
- Seats are ergonomic but very hard and noticeably close together
- Also: armrests??
- Shockingly good PA system though

Class 220 Voyager (CrossCountry)
- Both good and not so good
- Very comfortable seats, though legroom could be a squeak better
- Have a good ride and sound nice
- The profile designed to allow tilting operation makes them feel cramped and they have a tendency to overcrowd because of their route allocations
- The crampiness tends to be worse when travelling on them at night because of the way the lighting is inside
- They make the platforms at New Street unpleasant to wait on with their fumes ._.
- I hit my head on the vestibule ceilings

Class 221 Super Voyager (CrossCountry, Avanti West Coast)
Class 222 Meridian (East Midlands Railway)
Class 323 (West Midlands Railway)
Class 350 Desiro (London Northwestern Railway)
Class 360 Desiro (East Midlands Railway)
Class 390 Pendolino (Avanti West Coast)
- It's fast!
- Very smooth ride except for when it inexplicably judders forwards and back, which is somewhat frequently
- The tilt works and is very, very novel when you first experience it
- While the seats are very solid, they're also very comfortable - though you can see why they're gradually refurbishing these
- The doors take a comically long time to open and close

Class 700 Desiro City (Thameslink)
Class 745 FLiRT (Greater Anglia)
- I like these trains
-
The interior ambiance is really well done - the colour scheme and lighting come together to create a really pleasant and comfortable atomsphere.
- The whisper quiet and exceptionally smooth ride helps with this too
- There's plenty of luggage space (which is good, because these run the Stansted Express et al)
- I adore the level boarding system, plus the funky Jacobs bogies are fun
- Large, clear and crisp passenger information displays
- The same supportive seating as the WMR 196s, except with armrests, seatback tables and a better pitch
- Also has good looks outside
