Pros
Good software stack using the latest technology (.NET 4.5, MSSQL 2014). No overbearing IT department - I upgraded my machine to Windows 10 on release date. Tech management have technical backgrounds and are smart. Colleagues are smart and ambitious. CEO is a smart guy who regularly communicates with all staff through 'all-hands' sessions and takes questions on the direction of the company. Relaxed atmosphere with somewhat flexible working hours and the ability to work from home.
Cons
Career progression prospects are unclear. Moderate-high staff turnover rate (except for a few people who have been there since the beginning). No pension. Some poor communication from management. Poor software development practices - little testing (unit, UAT or acceptance), agile process varies between teams. Most code is in TFS, although some newer projects are now using Git. Poor benefits - don't expect any discounted tickets! People raise eyebrows when you tell them where you work (and explain what the company does). Recent layoffs have made people a bit nervous.