I've been to five different Oreganos in the Valley and each one is pretty consistent as far as food is concerned. All of them get very packed, there's a 30+ minute wait to get seated on weekends and a 30+ minute wait if you want a pan pizza. At least servers tell you that up front.
Servers are pretty friendly too. So much so that multiple friends think they have a shot at dating them by the time we're done eating.
We've chosen to sit at the bar at the Tempe location to avoid long waits in getting a table. Problem is, and I don't know if they do this at all the locations, they'll charge you for certain soft drinks (mainly soda water) at the bar but never when you're at a table.
I've never questioned it but I don't understand it.
Parking is pretty decent here and there's an abundance of chairs in the parking lot and reading material for people who are waiting to get a seat. There's a large outdoor seating section too, but I don't know if they bring the heaters out there during winter nights like they do in Mesa.
Even weekend afternoons here could warrant a wait. I'd avoid it during ASU basketball games or football Saturdays.