They are absolutely horrible, I can't stand them.
Free to play MMO's are a just vile, in my experience of them they have been far too cash shop based, ruined by bots and gold farmers and the support just isn't there.
The micro transaction is a great system, however the F2P crowd like to blatantly milk it in order to make the most money it possibly can.
This is fair enough, but when it harms the players in game experience that's when they go to far.
Everything in a F2P game is tweeked so that the CS offers considerable advantages.
You could just be Perfect World Entertainment and make a game based solely on Cash shop items, sadly that games does pretty well for itself.
Perfect World is actually pretty costly too and I don't equivocate when I say those cash shop items are necessary. For those who don't cash shop, you can buy your necessary heirograms from people who do.
That involves you going out and grinding for cash, which itself is pretty hard considering you don't have any heiros.
In the end I ended up spending about £20 a week, just on HP & MP heiros for my archer.
(I did sell a few for ingame cash)
Explanation: A heirogram is an item that a character uses as a health/mana potion. Players can buy bronze,silver or gold heiros, depending on how long they wish their item to last.
A heiro acts as temporary hit points, so a bronze hp heiro will come with 5k hp.
As the player takes damage, your hp will slowly be depleted but rather than dying the heiro will tick and take the missing hp from it's reserve.
Allowing the player to fight until the heiro is depleted.
These items are cruicial to playing in PW, as regular health potions just don't cut it as mobs hit considerably hard in this game and most players are all packing heiros in pvp.
You cannot play without them, I tried on potions and it totally sucked.
I spent more time grinding money for regular potions than I did grinding for exp.