I've thought about it too... For my Jeep Cherokee. $4500 for an old rusty truck that might fetch me $1500-$2000 if lucky isn't a bad deal!

What you do is your decision, naturally. The upsides: Your car will be newer, cleaner, more fuel-efficient and prettier. Downside: Working on it yourself outside of oil changes, brakes and other minor things will be MUCH harder, if not impossible without expensive diagnostic tools.