Pros
I recently interviewed and got a job at Moo. I was impressed with the speed and communication by everyone involved in the process. In total from first contact to an offer was less than a week. Everyone was helpful and friendly. There were two rounds of interviews - an initial meeting with the head of the team followed by a live code test (challenging but good) and questions from the team I ended up joining. After the offer everything was communicated to me clearly and in detail. I've been working at Moo now for four weeks and really enjoying the company. It has a small startup feel to it even though it is now relatively large.
Cons
None so far - probably only gripe is that there are more meetings than I was used to in a small startup - trying to find the balance is tough.