I remember reading an article recently which stated that the G1 Predacons were intended to be antagonists for the Dinobots, but it didn't eventuate. Can't find it now...
I'm also collecting the Feral Rex set and FT Dinobots, and I think they would look good facing off each other.
If it was G1 continuity I think the Predacons would win, even though they were beaten repeatedly by Skylynx. IDW comics, I would be favoring the Dinobots, even though they were beaten by Shockwave single-handed (HA!).