I believe there were some reports of TA rings not being too round. I don't really know of any good 110 bcd chainrings, I don't know any bad ones either though. Yes Dura-ace is a good cog. Most cogs are decent, you just have to make sure the threading is right for your hub. Chainrings and cogs, specifically, aren't good places to skimp. Especially when cogs are relatively cheap.