Vintage/Old air, worth it?

[muddpile]

I've been considering whether or not to put an aftermarket air conditioning system in my truck, and figured I'd get everyones opinion. It is not originally an air truck, and the heater just quit a few months ago (probably just the blower) so that got me thinking about a vintage air heat/cool unit. I priced this out, and for a complete deal it looks like it willrun me somewhere around $1500 candian, which is a lot of money considering the whole truck cost $1300. Do they heat any better/worse than the original, and are they difficult to install? Are they worth going with, or does everyone find that the windows down works pretty good? I'm just weighing out my options as I don't want to waste any cash. The truck will be a driver all 4 seasons here in canada. Its not hot a lot, but when it is, it gets pretty warm.