I've got a funny perspective on this, 'cos I'm in the process of doing my own MMO and I'm also planning on a microtransaction model.
It's tough to do microtransactions right, but the most successful implementations make the game free, with premium vanity items. Games like EQ2 (back when I played it) mostly sold things like furniture and fancy clothes to players, and people made extensive use of this. At the opposite extreme are games like Battlestar Galactica Online, where anything is available for player purchase, including fancy weapons and experience modifiers. There's a pretty large outcry about that from players who are (quite rightly) stating that there is no real incentive to actually level your character, when you can simply buy your way to an end game character.
In Eve's case, they seem to be chasing the vanity item model, but they're doing it in a weird way - we all still have to pay our regular subscription, and then we are allowed the privilege of purchasing vanity items. It's fine, suppose, from a game balance point of view. They're not selling anything that I've seen which allows new players to buy their way into being skilled ones. However, since they're still charging a premium price for subscriptions ($14 a month is not cheap in the MMO world), and since they also allow isk purchases (which allow people to buy things like t3 ships and officer mods with real world cash), I'm a little surprised that they're charging so much for these vanity items.
Then again, we're addicts, and I presume people are buying these things. God damn the pusher man...