Pros
The employee discount is great. REI offers benefits even to part-timers -- they're expensive, but at least it's an option. My coworkers were awesome and I had a great time on the sales floor, and for the most part my managers were respectful and communicative.
Cons
Selling memberships is becoming the single focus of sales performance reviews. If you work here, expect to push the co-op membership, and push it hard. You will annoy customers because by the you ask if they're members with REI, they have already been asked that same question by half a dozen green vests. I've heard from friends who still work there that the place has "gotten really corporate" even in the one year since I left. The store-sponsored employee camping trips, which gave employees a chance to try new activities, get to know their coworkers, and improve their product knowledge, have been canned because of "legal concerns". The system for promotions and advancement is completely opaque. I knew great employees who had been trying to get into management for five years, and couldn't make the move; meanwhile others who had been with the company less than six months were promoted. None of us knew how or why these decisions were made. I've also known of several excellent people who have been pushed out for completely bogus reasons in the past year -- and these are long-term, excellent employees who were beloved by customers. Some of them had even been on management staff for years.