It's basically a SASS eCommerce app. Kind of an enterprise class OLTP solution, but with pretty unusual traffic bursts and due to what we're selling very high DB contention. We test with 100,000 concurrent users, have achieved about 10,000 orders per minute--much more than our credit card gateway (Stripe) will allow us to process. There are some rough edges here and there, but I've experienced just as bad and sometimes worse with AWS.