Pros
Culture - You read in every company's 'about us' page how it's like a family, but iStream practices this every day. These were some of the finest people I have ever worked with.
Knowledge Share - the developers were some of the smartest individuals I have ever worked with, and they were not protective over their knowledge. If you were open to learning about the internals of banking and check clearing, this is a great place to do it.
Leadership - Face it; when people risk their capital to invest in a company, it's easy to pay all of your attention to the bottom line. The leadership of iStream honestly takes a balanced approach toward protecting their investment, and developing their staff. Opportunities to contribute are plentiful, and getting thoughtful guidance is only as hard as asking.
Cons
Pay and benefits aren't on par with larger companies in the same space. It's not bad, but if you're there for the money rather than the experience, you will be disappointed.