Pros
The first week at webapps consisted on bringing everyone up to speed with various technologies and languages. They gave us a run down of git (and the way the various projects used it), then a run down of SQL Server, JavaScript and a few other general things. Which while being a bit slow was very useful. After starting work properly I mixed with all the others working there and everyone was really friendly (and free [soft] drinks and breakfast is a massive plus!) . I was working on a new crossbrowser platform using all the modern technologies and gained a hell of a lot out of working there. Everyone was really really supportive and patient. Also, I want to talk about Craig (the CEO), who seems to be getting a lot of undeserved criticism. I agree, when you first meet Craig you get the impression he's arrogant, but don't judge a book by it's cover. You realise very quickly that he doesn't think himself better or smarter than anyone but just wants to push people to reach their potential and doesn't accept low quality hacky code. He makes it very clear that he would never fire anyone for disagreeing with him, and encourages discussion.
Cons
Like everywhere else, there are downsides. The main one as others have mentioned is the massive amount of legacy code which everybody has to maintain. BUT, they are slowly migrating their systems onto a new platform in which a lot of that is stripped out and is nice to develop against. It's unfair though to criticise a company for having been around for a long time, they're doing all they can to address that, nothing more anybody can ask of them.
