It's not exactly relevant to the original question, but sort-of. I have an Aoyue 968A+ that I picked up from someone broken/used. I replaced one of the potentiometers and all is well. It's a really cheap unit, but I've had great luck with it working on all sorts of surface mount componentry. This particular Aoyue also includes an iron with vapor removal. It's a "decent" iron, but the handle gets really hot. The additional tubing and nozzle for the vapor removal is a bit cumbersome to work with.
Overall, I'm pleased with the purchase and would imagine that similar hot air-only Aoyue equipment is equally fine. I can't really comment on the accuracy of the heating as I haven't tested it. Once set to a temperature that melts solder, it seems to hold that temperature well enough for my purposes.
I've even tried my fair share of BGA work with this guy. For those tasks, it's been less pleasing to use (seemingly due to uneven heating, etc.) I even tried buying a preheating station. It's just fiddly work that I find I don't enjoy doing. It's easier to just pay someone who has the "real"/automated BGA equipment to do the job.