I'm a reasonably well built 6"4', and I find Cross Country's Turbostars quite pleasant. What's wrong with upright seats anyway? Seems more comfy to me!
I used to find the Central 170s OK, but it's the recent refit that's cause me problems. Upright seats I prefer (the leant-back ones on the likes of 321s are a horrible angle, particularly for facing seats), but, because of the bulky seat design and metal backs, that means that I can't really slide my feet under the seat in front (assuming it's an airline seat, which it is 9 times out of 10).
If you get on a quiet service, and manage to nab a table seat with nobody opposite, then it's just about OK, although the curved headrest aligns with my shoulders, meaning I'm sat leaning forwards. However, as I normally use the trains on business trips, I'm not exactly catching them at quiet times...
Each to their own, of course, but I find the refurb a huge backwards step in terms of passenger comfort.