CircleBack's application process was fairly simple and straightforward. They offered me a lower rate than any of the other providers but be aware this is not the bank you should use if you're looking to build your credit. They delay reporting to the Credit Bureaus by 45 days "in case of charge backs" so the balance on your credit report is never exactly accurate. You can call and get a pay off letter emailed to you but I find this quite shifty.
Customer Service reps are hit or miss but no one is really going out of their way to help you.