BestBuy contracts out their refurb work to a "reputable refurbisher". That means they have some random-ass guy fix these things... These are NOT official MS repairs and MS will not touch the console if it craps out. You will be screwed out of your $150.
When MS repairs it, they replace the faulty motherboard or part. When refurbishers do it they generally repair the broken part as replacing parts becomes too costly (especially when you are a third party)...and it is easy enough to repair it. The problem is that repairs are not as reliable as a total replacement of the bad part would be, and when you repair a bad part it is still quite possible that it has the same defect that caused it to break in the first place, therefore the repair will eventually fail. And in my experience, more times than not, this is what happens...
As a person who refurbishes xbox 360s himself, I would never trust anyone else to refurb my unit. There are no set standards when refurbing and no way to know how good a job was done, or how long the unit will last before erroring again. Also, some people just dont know what they are doing and it becomes shockingly apparent when opening the case and seeing what has been done inside. Unless you get lucky and get a box that only had a DVD drive problem, chances are that the xbox will break again and you will be out your money since Microsoft will NOT touch the console when it breaks again. Also, since it was refurbed by a 3rd party, the warranty seal will be broken and thus the warranty will be obviously void because of that reason as well. If it is past 30 days, BB wont take it back as a return either apparently.
I have seen so many
ed up units because the person who refurbed it didnt do it right and for that reason the refurb didnt take properly and the unit red ringed much quicker.
As a general rule, refurb xbox 360s are a no-no. You are opening a whole can of worms that is better left closed. Spend the extra $50 and get a 4GB unit. Then buy a cheap old-style HDD (you can get them for a lot cheaper now-a-days), open it up with a screw driver, and stick the HDD in your slim.