RE: gearing -- I've gone down from a 50 x 11-28 back to 50 x 12-27 because I found it was about the same result to just coast in the rare instances I would shift to 50x11. For me, on ten speed 11-28 has some mighty jumps where you are either mashing too slow or spinning too fast to fit in with group rides. I imagine the 53 or 52 chainring would be good if you either like using your small chainring a lot or you're doing hard sprints and intervals. Probably not the best combo for beginners.
Groupset is fairly irrelevant this day in age unless for the bling factor. I have 105, shifts great on my road bike. I also have a combo claris/tourney on a CX bike, shifts great too.