I prefer constantinople, it helps you to ensure that no one can kick you out of bulgaria. Unless, of course, you lose the black sea, in which case, you're screwed anyway.

I preffer Constantinople as well, it leaves you uncommitted and my favourite anti-Russian move is convoying to Armenia once I'm settled in the Black Sea anyway.

The Armenia opening does not get you into the Black Sea at the end of 1901. When you move to Armenia, it's fairly clear you're almost certainly going to move Bulgaria to Rumania and Armenia to Sevastapol. Russia can gamble on this to move Ukraine to Rumania and Sevastapol to Black Sea, so everything Turkish bounces. At this point, Italy is doing one of two things - diving into Austria - in which case Russia gets Galicia in the Fall - or Lepantoing with Austria in which case Turkey has bigger problems. In short, I don't see why anyone would want to play the Armenia opening. It doesn't get you anywhere, unless Italy is extraordinarily incompetent, or Germany is also after Russia with England.

personally, I find myself torn every game. I find that Armenia puts immediate stress on Russia, and, in conjunction with austria and england, can deny russia a build in 1901, which really opens up the turkish position, which could offset a potential lepanto. and of course, armenia can really screw russia if he moves fleet to rum or moves moscow to st petes. however, a solid austro-italian alliance combined with pissing off russia can make armenia rather ineffective.