Pros
If you want to become an expert in Microsoft Techonologies, this is (aside Microsoft) the best company to be. Parttime work is no problem and they have a great work-life balance. They offer free access to MSDN, which is great if you want to get hold of the latest Microsoft software. Pay is ok, you get a laptop, car and some small perks like they paying for your broadband connection etc.
Cons
Being a subsidiary of Accenture and Microsoft, it often happens that Accenture has the lead in the project. They tend to see programmers from Avanade as 'production units', write the code and write is fast. If you are someone who just graduated and you don't want to go into programming but want to get into IT strategy, information management, business IT processes, etc., forget it. They say you first have to start on technicall jobs before you are able to say something meaningfull about business IT processes. They seem to focused on Sharepoint implementations only lately, there is a great demand, thats true, but if all they seem to have is sharepoint then there isn't much choice is there? Also we have seen several senior management leaving last year, heard stories that Avanade isn't the startup-like company it used to be.