Ventajas
I worked for two years as a Sr. Systems Engineer at the San Francisco office and it was honestly one of the best work experiences I've had. Engineers (in SF/LA at least) are paid on an hourly basis, that alone made this job AMAZING. Anyone experienced in this area knows the amount of after hours work involved; actually getting paid for your after hours work is far far far better than comp time for a salaried employee. I remember putting in a 70 hour week recovering an entire server farm due to a ransomware outbreak and didn't complain once, how many salaried employees can say that?
Benefits are good. Pay is good (I can't stress enough how great being hourly is). The job has a good work/life balance with the option to work from home when you aren't needed on-site.
I can only speak for SF but management was great. You don't have to worry about micromanagement as long as you were actually doing your job. Want to work from home this week? Fine, you won't hear a complaint as long as you are meeting your billable quota and making the client happy. A lot of MSP's using the term "consultant" but this is one of the few companies where you are actually treated like one.
I moved out of state so I had to leave the company, if not I'm sure I would still be chugging away happy as a clam.
Desventajas
We had a lot of turnover in a short period of time in 2015 (see negative reviews), upper management didn't really address this with most of the engineers; this left a lot of us with a poor perception of the company. In SF it wasn't so bad since we were a tight knit group but it really affected the LA office. I think the company has bounced back since then and it was doing fine when I left in early 2016.
Project management is non-existant, this is left up to the engineers. Personally this was great, for some engineers not so much. Many of the larger projects could have really benefited from a true project manager.