We launched ESX - xCatalyst just under a month ago. I would say, without hesitation, that the xCatalyst platform is extremely flexible, and the company is excellent to work with. They are very fair, and very good at what they do. At the same time, I would have to say that they are primarily engineers... meaning... they give you what you ask for, and not always what makes the most sense. Case in point: We had a specific feature that they implemented for us. In our old custom solution, it worked slick and everyone was happy.