Presumably there were some risk factors in your case that meant that they rejected you, it would be much more helpful to everyone if you specified what they were (i.e. you were in a high-risk industry like gambling, ticketing, etc.) that way people would have a better idea if what applied in your situation would also apply in theirs.
I can provide a counterpoint - we signed up with Braintree a few months back and their service so far has been nothing short of stellar. Nice API, well written client SDKs and a support team that you can chat to about code and get responses from very quickly. We found the signup process to be smooth.
Only to be told that my 6 year old business that has been in profit each and every year and does a respectable 6 figure turnover is "too risky"
fuck that