Pros
I joined as a graduate with basically no IT or consulting skills. By the time I left Customer Systems a few years later, my prospects had changed hugely. I learned an unbelievable amount, both in technical and non-technical areas. I was paid very well and my career progression was accelerated in comparison to those working for bigger companies. At the time, I probably didn't realise how much I was getting out of my employment, but with hindsight, it was a fantastic place to start a career. Working for a profitable company is a good thing and the MD knows how to make a profit. This is important and often overlooked.
Cons
Some of the cons listed in other reviews appear to be based on truth but greatly exaggerated. From my interview, I knew that I would be expected to dress smart and work hard. I think it's worth noting that Customer Systems employ a lot of people straight from university and that employees can quickly lose sight of how much they are being paid as a graduate. Getting paid £50k to wear a tie as a graduate does not make you a slave. However, the evidence shows that some people are a bad fit for the company and do not enjoy the job, so bear this in mind when applying.