I left WoW and went to rift as they atleast deliver monthly and aren't in a position they can release small tidbits of content and still keep people paying and seeing i did it and others i know did it, that's all the matters to me.
That being said my server is well populated, we get 40-80 people while leveling to participate in a zone invasion on a single faction and my WF group is also populated enough that i get during the middle of the night in odd level ranges WF's to pop up that are of notable size.
From my opinion Rift is surpassing WoW in terms of delivering content and improving their game, while raid encounters are still more complex in WoW i'm sure at this rate we'll get that there in rift aswel. I see no reason to keep paying for a company that supposedly cannot create new models for their content patches yes i'm refering to ZA/ZG which is basically criminal seeing what they earn of subs but can divert that time to create an Ipad version of WoW and can make time to create new models for their cashshop. Being fucked over and paying for it, i think i'll pass.