Pros
Good experience for someone looking for their first real office job. Relias seems like the kind of company that people fresh out of college would be drawn to. They offer perks such as an on site gym, specialty coffee, and even table tennis. As you get a little older or further in your career, however, those things have much less cachet and you'd certainly rather have the extra money in your pocket or better insurance. It has almost a disingenuous feel as if management is saying, "Look! We're like Google! Look at our funky furniture and open office floor plans!" Yes, Google has a lot of similar perks...they also pay their people a whole hell of a lot more and have extremely generous benefits to boot.
Cons
While having a lot of young talent around makes for a lively company with fantastic diversity, it also breeds cliques and in-groups. If you're in the "right" group, you can go pretty darn far in the company with little to no experience necessary. If you're more of a methodical thinker in your work ethic, I promise you, you will not be noticed at this company. If you aren't the loudest person in the room, you will not be heard. This is the sort of thing that burns out great talent very quickly. Turnover at Relias is the worst I've ever seen at any of the places I've ever worked. People stay for about a year and move on.