Pros
You really can't beat the discount. If you can get a decent manager you can get even better deals! As a technician you will see a wide variety of technical problems and you will get some great experience. Remember that now a days customer interaction is important and is a marketable skill. Best Buy lets you develop that as far as you want to take it.
Cons
Politics, Politics, Politics - It's a good old boy environment and the biggest problem is that people get promoted that shouldn't. This kills moral something fierce and is really something that should be addressed. You have to have confidence in the manager to lead and when the reason that they get promoted is because they are drinking with the GM that isn't very production. There is also the relationship issues. Managers will often date the young girls and as a result they get special treatment. It's gets worse when people break up or they start dating multiple people in the same store.