Drak, you misunderstood me I think mate. The crappy gun problems are user error defo, i don't dispute that but my HVLP gravity fed was MUCH easier to learn. For the little extra it cost it made my life easier and I had to practise a lot less. I am lazy and impatient so it was the best buy ever. I want to spray a guitar not mess with practising. I use my gun a lot on motorcycles and the odd car panel so it's important I'm spraying not learning. I still agree that no one should spend silly money though. If there's a local automotive repair suppliers near by, they usually have what I need and I get it at a decent price.
2Pack is literally a 2 part acrylic enamel which is used in automotive repair over here and replaced Celly totally quite a few years back. It's basially a resin and activator which chemically harden rather than relying on evaporation. The main problem is, it's poisonous and nasty for the environment so most of us are moving over to the new water based versions. 2pack (or 2K as it's otherwise known) is a bitch to use well and you need an air fed mask or your lungs will just stop working one day - it really is that bd and has cyanide as it's main component! Here's a good link with some basic info. http://www.austinsevenfriends.com/paint.htm
The benefits are great though. It's as hard as nails when it's cured. The curing time is easily cut down to 40 mins in a commercial spray both over but decent infra reds will get it down to a coule of hours or a week if not heat used. It NEVER yellows and each coat goes on quite thick so there's only about 4-5 coats on the guitar - less spraying and less time to using the beast!
If you don't clean your gun well, you might as well chuch it in the bin.
The secret I think is a good balance between quality and price. A decent gun will be easy to set up and you will get a decent finish quickly but an eaxpensive gun will be a waste of money if you spray a couple of guitars a year and nothing else.