Ride the bikes, and pick the one that you like best. Don't over-analyze, or you'll never get a new bike. And if the shop you like doesn't have the bike that you want to road test, then go to another shop that does have the bike. A bike with the same frame, but different group set is close enough as long as it is in your size.

If none of the new bikes are screaming for you to buy them, then keep riding the old bike.

GH