Frame vs Groupset
New bike time: looking in the £1,500 - £1,800 bracket and I'm faced with a balance of better frame (alu vs carbon vs erm, fancier carbon) or better groupset (105 vs Ultegra)
For example, Giant's Defy series offers a composite version with Ultegra or an advanced version with 105 both for roughly the same cash and finishing kit/wheels. Similarly, Cannondale's Synapse Carbon 5 (105 carbon) and CAAD 10 3 (Ultegra alu), although they have different geometry and aren't real like-for-like comparisons.
Assuming that all else is roughly equal (wheels, finishing kit, etc) which should take priority - frame or groupset?