I have an 8586D. The hot air side is great, I highly recommend it. The soldering side is just OK. It takes a while to heat up, and it's only bang-bang control (not PID), and has no digital temperature readout. I got it because it was almost the same price as the hot-air only version, and it seemed useful as a portable all-in-one unit. It's definitely not Hakko quality, but it will get you by for a while if you are tight on cash. The included tips will last for a while. You can always pick up a better iron when you have a bit more money--the iron unplugs from the unit so it doesn't really take up any extra space when you get something better later on (you can still use the hot-air side).
Hope that helps!