Pros
The people are first and foremost the biggest pro. Everyone is just a pleasure to interact with and the partners are truly the most kind and caring people you will ever meet. Their attention is on the people first and the business second. Not to say the business is ignored, just that they understand it's the people that make up the business so they deserve the most attention. The quality of work product is extremely important to everyone and there is a fairly unique prioritization of technical writing. I dare someone to find a perk that TERP doesn't offer that another company does, or one that is better than what TERP offers.
Cons
It's a growing company, so that comes with growing pains. Nothing that is worth complaining about, but since I am asked to list cons...