Pros
QTS is a good company with heart, quality products, and caring folks. Just like a lot of places, sometimes the politics of 'getting ahead' or 'protecting my turf' get in the way of progress and growth. That's unfortunate but people are people I guess. The good thing is the culture tends to win out and the company does make the right decisions for the right reasons the vast majority of the time. That's really important!
The company has seen explosive growth so if you are a go-getter you have a great chance to be successful and grow with the company. If you need rigid structure and process to perform your job, you'll quickly see the holes that you have to fill in yourself to be successful. That can lead to frustration, confusion, re-work, and sometimes turn-over.
It has the feel of a family start-up with sound financial backing. I think that's what makes it fun and exciting - others may disagree. Technology is moving so fast these days I don't know if QTS will ever catchup to being an automated-process heavy enterprise. Perhaps it's better that way, anyway?
Cons
Sometimes the wrong people are hired or the wrong decisions are made that aren't a good culture fit. These setbacks hurt growth and morale.