Pros
Unboxed have a great culture and are very welcoming. There is purposefully a lack of hierarchy at Unboxed which encourages employees to take a more self directed approach with their career. You're encouraged to get involved with extra curricular activities, but unlike some other companies you're not judged negatively if you'd rather just do your job and go home. It's very much each to their own at Unboxed and I think they realise that everybody is different and that everybody can contribute in their own different way. Unboxed have a very relaxed and flexible working environment and are usually extremely accommodating to what might seem like outrageous requests at other companies. If you have any issues it's very easy to speak to one of the management team and they will try their best to help you out. Lunch time board games are popular and they are a great way to relax and get to know everybody when you first start at the company. From a developer's perspective, the Unboxed CTO (Andrew) is a Rails core contributor, and working with him has massively improved me as a developer, even in the short time was there.
Cons
Because of the nature of how Unboxed operate, sometimes you are asked to move projects at a moment's notice, or asked to work on a project for just a week or two and then move back to your other project. This isn't a negative per se, it's just something to be aware of. If you're somebody who prefers a more settled working environment, Unboxed can accommodate that (some developers have been on certain projects for a year or more) but it's worth pointing out that this may not always be the case and you may be chopping or changing projects depending on which projects come in. The only con I can think of would be salary. It tends to be slightly lower at Unboxed, but this is the sacrifice you make for working in such a relaxed and welcoming environment. If you're a junior to mid level developer, I really don't think there are many better places to learn your craft. Apart from salary, there really aren't many cons to working here. I can safely say it's the best job I've ever had.