Pros
I've been employed at eBay for 3+ years and have been in the software industry for > 25 years; eBay is the best company I've worked for in which your work ethic, skills, innovation, etc. is the basis for your reviews and advancement. If you want to come in and work hard, innovate and really advance your personal skills and abilities, eBay allows you to all that and more.
Cons
All companies have some level of politics and of course eBay is no different, so if I'm looking for a con, that's about the only one I can really point to from a company perspective. The only other con is that many people who join eBay are very technically strong and looking for a new challenge monthly (weekly, daily even for some) which leads to quite a bit of attrition. This level of attrition can make your job harder b/c the service, module, component, etc. that you need to interface often no longer has any original authors or true owners.