If I am not mistaken the current 105 is an old Ultegra, but I don't know how far back. My bike is 2007 105/Ultegra mix and shifts very smooth. DH rode it and said he finds it nearly as smooth as his 2004 Dura Ace. I can't ride his bike so I couldn't tell you if that is true. The current 105 got a good review from the guys at CyclingNews.com.

Does your awesome shop give you perks for buying from them like free tune ups? That would sway me to stick with them personally.