What should I look for in a paint spray gun?

[Joker]

I'm thinking about buying a spray gun to paint our fences, which are a little old and unslightly at the moment. They seem pretty cheap and I hear they save a lot of time compared to using a brush. I'm just not sure what to look for. Anyone got any tips about what to look for and what to avoid? 

[KingStreetReno]

I recently bought the Dulux Rapid Finish spray gun to paint my fence. See post here. It was only $99 and worked a treat!

http://www.bunnings.com.au/dulux-rapidfinish-paint-spray-gun_p1560480

[Farleys]

I borrowed one recently from a friend to paint an old fence. It was only a cheap spray gun but it was really easy to use. I'd just make sure they are easy to use and easy to clean. You certainly don't need to spend a lot of money if its just to paint a fence. I imagine the better ones are more important for getting a nice even finish with indoor work.