Pros
You work with great people for an ok/decent hourly wage if you're single. The full benefits are good too. Even though health/dental/vision comes out of your paycheck, it's still nice to have. The 401k is great and I don't know of any better employee discount than Best Buy's. Lastly, just being able to drive out and meet all kinds of different people instead of being stuck behind a desk or inside a store all day is great. I've seen more of LA than anybody and I get to see it every day.
Cons
For one, don't expect any training. Best Buy is synonymous for throwing you out to the lions and saying "Good luck, don't screw up." Second, if you have a significant other and live anywhere where the cost of living is a bit higher, you'll find it hard to stay afloat. Most of my colleagues are in pretty rough spots. While the pay is ok, it's still less than what other companies pay for an "IT specialist." Third, you'll be working for a company that is trying desperately to reinvigorate itself and its image. Fourth, while you will be out in the field, you'll also be stuck in a vehicle for a greater portion of the day in traffic. This gets old very quickly. Fifth, kiss your life goodbye. By the time you get home, you won't want to do anything but rest. At one point, my wife complained that she never saw me due to the overtime I had to put in to get all of our jobs done. Lastly, it's incredibly difficult to move up in the company. It took me almost 5 years to go from the store position to this field position. It's all about who you know.