The BGE is an excellent smoker and a decent grill, but without some modifications, you can't create a two-zone fire like you can in a kettle. The more I use this method in the kettle the more I wish the Egg had a way to do it. I might get inventive and make something...it would be easy enough, but my point is, that is a very valuable technique that the Egg Heads say you don't need. If I were doing it again today, I would look at the oblong Primo and most likely go that way. The Primo does have facility for a two zone fire, and the oblong shape lends itself well to briskets and ribs, my two favorite cooks.
Oddly enough that you ask the question, as in 1999 I sold a Performer to get my first Big Green Egg. I think if I had been a part of this community and had learned to get the most out of my Performer, I might not have done that.
On the other hand, the Medium Big Green Egg that I bought in 1999 I just sold a couple weeks ago for exactly what I gave for it brand new. How many grills hold 100% of their value over time?
Not sure what type of cooks you're looking to do with the Egg that you can't do with the Performer, but if it were my money today, knowing what I know now, I would get a Cajun Bandit Stacker, a CB Rotisserie a few fire bricks and take the other 750 dollars I didn't spend and head to the meat market.