Was very surprised at level of service.
My experience:
Flying economy G, star alliance gold status.
Lines at IAD crazy, but *A Gold use biz class everything. Queues, priority boarding, passport checks (not visa line), transit, etc.
Strict in cabin baggage rules (7kgsmax carryon roller board) didn't seem as strict for *Agold.
Seats- good recline, but very hard seat cushion. We both ended up flying with head pillow as extra seat cushion. :-)
On iAd/ist they baked bread on board.
Service very attentive and friendly - UA could learn something from then.
If connecting, be sure to print all boarding passes before ist. Otherwise, have to go to three different transfer/security desks. You can bypass from arrival bus, otherwise.
Lounge has lockers for luggage, great for storing when doing a quick sightseeing run into Istanbul. Huge plus. Note, they clear them at midnight.