Originally Posted by
ShortLegCyclist
CAAD 8 geometry is racier and less relaxed than most entry level road bikes so what felt great on a two minute test ride might not on a two hour outing, but that is something that IF it bothers you down the line can be adjusted to some extent by raising the handlebars.
My understanding is that the Synapse is their endurance geometry model and that is what I've recommended friends of mine who are just getting into road cycling look into rather than the CAAD bikes.
The CAAD10(now 12) is Cannondale's aggressive bike. The CAAD8 is a more relaxed version, not as much of a heads up ride as the Synapse, but not as aggressive as the CAAD10/12. Similar to the H2 fit on the Madone/Emonda vs the aggressive H1 Madone and endurance Domane.