Pros
REI was a fun place for me to work in 2010. Between the great pro-deals, other benefits, and fun coworkers, it was the best retail position I've worked to date. The pay, while not amazing, was better than I had been paid in other retail positions. I also enjoyed selling quality products to people and REI's company values (i.e. educations, conservation, etc). It was a really great job for me at that time in my life, and I would generally recommend others to work there too.
Cons
Unfortunately, it's still a retail position, so hours can be all over the place. It can also be difficult to get on as a full-time employee, which can make it hard to support yourself with just 1 job. While I was there, the multiple systems we had to use for customer service were cumbersome and frequently very frustrating.