Originally Posted by
WalksOn2Wheels
As an example, the DA9000 on my Domane was new when 105 5700 was the standard "entry" level. Like a year or two later, 5800 came out and is a carbon copy of all the architecture of DA9000, just less carbon and fancy metals so it's a little heavier. And aright around the same time, the new Dura Ace showed up. Marginal gains and all that...
That reminds me, I need to see if I can score a 5800 group for cheap now.
You can get groups at reasonable prices stateside, but the best prices that I've seen are still in the UK - Merlin is still shipping Shimano to the US, but most (like PBK) aren't any longer. If you're looking at hydro, Merlin's the best I've seen by far.