Pros
You can understand the direction the architecture profession is going when you look at RTKL. The firm lets the employee "take over" to the extent of that employee's own level of competence and mental capacity. In that sense it's very challenging only if you are motivated enough to make it that way. If you want to do or say something, then do it. Learning is a MAJOR component, especially if you are "fresh off the boat" (out of architecture school with no experience whatsoever). You get to learn about the 21st-Century Professional-Practice "Best-Practices" side of architecture.
Cons
Forget design. At least in healthcare, the deadlines are too tight. Very understaffed. Very similar to the level of intensity that is expected of a student in graduate architecture school. Everything is by the seat of your pants, the only reason why the hospital didn't fall down is because some intern-architect was really, really good at their job with more initiative and education than what would be considered even close to reasonable. The pay is a lot more than what you can expect at most architecture firms in the United States. Therefore, the pay is only poor at best (you actually get to make more than someone who works at McDonald's !!!). Therefore, to say that RTKL is a bad firm is equivalent to saying that the entire architecture profession in general is bad (which it is). If us architects want to make more money, then we need to be as aggressive, ruthlless, and unsympathetic as the rest of this nation's professionals. If we want to get paid what we deserve, then we should stand up for ourselves. End of story. In other words, RTKL is one of those firms that blinks and does not stand by its own principles, just like the rest of the entire architecture profession. We are all so weak.