would you still buy a Kamado (primo) if you had a weber performer and wsm

If you want it and have the money buy it.

I would but only a jumbo xl for me otherwise I don't feel that I would have enough space for what I would use it for.

Didn't see your location but one thing a kamado can do that a weber cant is smoke consistently in lots of different weather conditions. I picked up a Akorn Jr. and the main reason I convinced myself I needed it after just picking up a OTG was that I will be able to use it her in MN over the winter to do longer smokes.

Another related benifit I've noticed with the kamado is how efficient it is with charcoal. I can get just about as far on the Akorn Jr. with a single 8# bag of lump as I can with closer to 40# of KBB on the OTG.

I have all three (sorta, I have an OTS not a performer but whatever) and the simple answer is yes.

I do all my outdoor cooking on metal Webers. I've cooked on BGEs and had food cooked on them by others and the food was great, but I'm happy with what I've got. Don't get me wrong, I would take one if you gave it to me (I'm in Marietta, GA near Roswell, GA and can give excellent directions).

I have to say I love having both. The Kamado is extremely versatile at many different cooks but it can't get much easier to smoke on @ low & slow cooks; love the high temp cooks for steaks, breads, & pizzas. I will say though that I use my Weber performer 85% of the time & my poor Weber Summit is used for holding foods and the occasional rotisserie items (albeit I usually smoke them for a while before hitting the gasser)

Buy it, you can always sell it.