I've never taken Effexor. I've had experience with Wellbutrin both as XL at 300mg and as SR at 150 (though that may well go up a little soon). The XL I was taking when misdiagnosed, and therefore w/o mood stabilizer. It was the least problematic of the ADs I was put on at the time. SSRIs were a disaster.

The SR version I'm on now in conjunction with lamotrigine for mood stabilization. (The SR because it has a generic and I have no insurance, yada yada). It's helped. We'd tried just increasing the lamotrigine (up to double what it is currently) and it just wasn't really doing the trick. Adding the bupropion seems to be doing the trick.

Everyone's different of course, but that's my personal experience.