Pros
Manageable stress level. Never had a direct manager who wasn't great, though I'm sure not everyone would say that. Clear expectations. Fair but not particularly great pay. Good training (wasn't always the case) but L&D is much better than it used to be. Development opportunities are plentiful, you just have to pursue them. Vendor partners, at least those I've worked with, are great. Lots of freebies. Bonus and spiff potential is good with most sales / market development positions. Lots of ways to make inroads with vendors and successfully go work for them in a sales capacity (which is where the big money is in the IT industry). A great stepping stone - lots of places to move up internally and in the industry.
Cons
Repetitive, boring work. Not intellectually stimulating in any way. You really have to pursue development opportunities and extra projects to stand out. Most managers are great, but some are notoriously dysfunctional and actively embrace favoritism (though that hasn't been my experience, but I've seen it). Archaic systems, confusing processes. Order fulfillment and cost adjustment processes are slow, can impact speed of sales cycle. Large organization, moves slow.