Pros
Very good health insurance, Very good retirement plan, very good discounts, fun events, being educated by the best reps in the world, having access to a lot of really cool equipment. If you want to meet like minded people and do fun things with some pretty cool co-workers in your off time, this is the place. Very very good discounts on the best equipment and clothing. It could prepare you to work at any level in the outdoor industry. You can get in great shape with all that you do there physically.
Cons
You probably won't see the cons until you are a few years in, it starts out great...In my personal opinion REI does not pay a livable wage for many people (retail, I know). Many co workers will be making 33 percent more that you. IMO you should only work here if 1. You are in college or high school, 2. you are independently wealthy, 3. Your significant other or family can support you, or 4. You are retired. 5. you want to build up your equipment. (Some other things)...If you work at a great store, your management may be different from mine (and there are locations with fantastic management) however my managers did not lead by example. Most of the time they were in the office. Managers will very rarely back you up with customers, they prefer you to be subservient to themselves and customers even though you are the one who is teaching each customer how to enjoy themselves and stay safe while enjoying the outdoors. Internally, they are constantly pushing you to sell memberships. REI is (IMO) moving away from selling equipment. Now they are basically pushing their own line and they might as well be a flagship store. If you want to deal with screaming 17 year old high school students who can't find the right down jacket this is the place for you. Also, customers will constantly be trying to scheme on returning items. I have had people try and return tents that are 22 years old. This is an average day. I could continue. Basically I loved REI as a customer prior to working there, and I think it's best to stay a customer. My store was all based on manager favorites.