Pros
Probably the most comprehensive source of MS contract positions. Presumably competitive salary and benefits, although I wasn't employed long enough to take advantage of the latter.
Cons
Atrocious manager feedback, containing absolutely no actionable information. My Excell manager would simply regurgitate things she had been told by my lead, but with no understanding of the original context (or of what her notes even meant), she was completely at a loss to tell me how I could improve things. As a result, our monthly "check-ins" were a waste of time for both of us. By far the worst aspect of my time with Excell, though, was the fact that they ended my contract per the original schedule AFTER promising me (in emails which I still possess) that it would be extended a month from the original ending date. I came in on Monday to discover that my cardkey no longer worked, my email address no longer existed, and, indeed, I had been completely purged from Active Directory and all other internal Microsoft systems. I called my Excell manager, who professed surprise, said she would look into it, and finally called back at the end of the day to inform me that "there had been a mistake" and my contract had expired per the original schedule. There was absolutely no attempt at any apology or explanation, or indeed any acknowledgment of responsibility whatsoever. I am furious about that, but it is still a relatively minor inconvenience for me - a few weeks of job hunting with no salary in the meantime. For my Indian officemate (who received the same false promise of a month's extension), it is much more serious - unless he finds a job immediately, his legal resident status is in jeopardy. Excell deserves to be sued for this level of malfeasance. I would urge anyone to avoid Excell as long as this kind of incompetent (or dishonest - I'm still not sure which) behavior continues.