Pros
Mthree is really as good as it sounds. I come from a non traditional background as software engineer. After switching careers and finishing a boot camp, I heard about mthree and decided to join. The training was really good but don't expect to fully learn java in a couple weeks. It takes lots of independent study as well. I was placed with a bank and the experience was invaluable for my first time working as a software engineer. The mthree team is also very supportive and helpful, just be sure to submit your timesheets on time. Its been almost a year and I know a few of my peers have been converted already and I might convert soon according to my manager.
Cons
It's possible the jobs available might be in a different part of the country. But I had friends who couldn't relocate and or weren't placed in the first round and they had additional chances to interview for a position closer to home.