Get your credit right before going here. I was upside down, and thought that I was approved for a loan and wasn't. I found out as much when I had to return the vehicle that I assumed I was approved for because I signed all of the paperwork and drove off of the lot! It wasn't so.
The good thing about the experience is that I was over my head and in too deep with the loan that I was attempting to get anyway, so I sort of saved myself some heartache.
Other than that the customer service isn't bad, someone will see to you right away as soon as you walk on the lot, and others will ask if you've been helped while you're waiting on your salesman to get back to you.
But if your credit is really, really poor (like 300, or bankruptcies, student loans and the like), go to a buy here pay here and save yourself the heartache.