I bought my Blazer used with 90K(kms) on it, and it's been a blast. This is my 5th Blazer/Jimmy, and they're great vehicles if you know what to look for. The following problems are a given after about 120k: ball joints, leaky oil lines, heater core, squeaky rear window, recliner handles will break off, door hinge bushings, and if not maintained properly, auto transmissions will probably go around 200k. If your vehicle still has Dex- cool in it (orange anti-freeze), I would highly recommend getting it flushed and replaced with the regular green stuff, and that may save you some headaches. The fuel economy is not great, but like most vehicles, maintain these properly and they'll treat you well.
Decent power, lots of interior space for it's size, great interior/exterior design.