Pros
Their screening process is based off of potential, not pedigree. The test you take doesn't care what color, gender, or age you happen to be, just how well you perform. As a result, the race an gender distribution far exceeds that of other software companies. Also, some of the best people I've ever had the privilege of working with survived Catalyst.
Cons
Last year there were three deaths in a company of around one hundred people. They were all tragic, but one in particular stood out as symbolic of what it means to work for Catalyst. He was a young kid who died homeless in their parking lot despite being one of their "Rising Stars". Many will point out he frequently said he was okay with living out of his van, but I was there when he switched from coming in about five minutes late every day, to coming in two hours early because he had nowhere else to go. In fact, I had lived it, so I knew exactly the pride that kept him quiet about his situation. I keep wondering if Catalyst had paid him what he was worth, if he wouldn't still be alive. This is a company that will bill you to their clients as senior developers, or leads at a rate of $86 to $120/hr while only paying you $15. You will often work with developers from other companies at the same caliber, doing the same job, but being paid three to four times as much. I guarantee this will eat away at you, despite the idea you're getting good experience for jobs elsewhere. Their training is about as smooth and consistent as headcheese. More often than not you'll get a former student desperately trying to do the right thing, but not qualified to teach at the level necessary to become a top developer. Sometimes you'll get a babysitter. On rare occasions you'll get a fully qualified developer to give instructions, but then leadership will do everything in their power to screw that person over so that they'll leave the company (after all, teaching isn't billable, so leadership treats said teacher as a liability). This leads back to the lucky training cycle being stuck with either a former student, or a babysitter, or sometimes just no one at all. They will also bill the state for workforce training grants and kickbacks, and once they've pocketed the money, leave you to rot despite their agreement with state agencies to do continuous training and job placement. After they've pocketed all the taxpayer money, then they'll think about putting you to work. Finally, the two year contract. I'd love to write a hundred page novel of expletives here. Instead, I'll point out Catalyst employs multiple law FIRMS for the purpose of processing, suing, and garnishing current and former employees. They genuinely have more lawyers at their disposal than tech leads. If that doesn't tell you what kind of company this is, I don't know what will.