I still have 3 months subscriptions in WOW before I picked up this game.
After I got the game, I seldom step foot into WOW again except 1 or 2 times (While swtor is in maintenance) just to see if there any guildies or friends to chit chat.
Before Swtor, all I do in WOW is just to complete LFR for my 5 toons and cap VP for the week, occasionally run DS normal with guildies. After I got Swtor, I am enjoying the game and never look back to do my usual stuff in WOW again.
Sure Swtor has its bugs but so far it not too critical to keep me out of the game. I am sure the game will just get better over time as it is barely 2 months since launch.