So I've been taking photos with my Canon 600D forever now, and I've been pleased with most of my results. TBH, the times I've been disappointed, it's probably not because of the camera. However I've been dying to get my hands on a full frame body, with slightly better IQ and the extra use of my 50mm f/1.8. 

Now, is the Canon 5D Mark II still a great camera? This of course being compared to my 600D. I don't care about the extra weight. The reason for asking is that it was released two years prior to the 600D, did that much happen? I mostly shoot people—friends and family—portraits, and candids.

And yes, I have a few L lenses, so I've already upgraded that part.

Thanks in advance, please tell me to add info if needed.