Re: which quad is best for me?
IMHO, the best quad you can own is definitely not a Yamaha, it's a LT500R (Quadzilla!). The Banshee is a decent scoot, and so is the Blaster, which for your age and size would be the better ride of the two.
I'd look for a used LT250R if I were you, they can be had for fairly small coin (85-92 were the years of production), and were prepped as well as any newer ride right out of the box.
My 500 (88) had a much better power to weight ratio, better acceleration, and far better suspension than my buddy's 98 Banshee, and was far better constructed (totally factory too). Yes, itd blow me away on the straight flats, but in the dunes and corners, there is no comparison. We both sold our rides at the same time, and I got $4,000 to his $3,200.
Don't count out the other rides yet - do some research and you'll find that the Yamahas aren't the only "non gay" bike out there.