Pros
If you work in the Professional Services are as a Cloud Engineer, chances are you will work with smart people and do a lot of net new work. Satisfying and great opportunities to learn new technologies and open minded engineers will keep you from getting bored. Pay is good, but doesn't keep up over time. If you're not in Professional Services you're probably in Rackspace. Onica was acquired by them and they do not operate the same.
Cons
After the Rackspace acquisition a lot of talent left. The company is understaffed so they are working extra lean. If your team needs help and nobody is free, you're out of luck. Most of the people who left were Seniors, so there's a lot of inexperienced talent; some great, others still learning the ropes. Benefits are decent but outclassed by other companies.