Avantages
The people. My colleagues were trusted friends as well as respected co-workers. There are loads of talented people to learn from there. Also, the business is just plain fun. Since so many people make a living selling stuff on eBay, being a part of that can be incredibly rewarding. You feel like you're part of helping people - giving them tools to make their lives better.
Inconvénients
Management changes strategy at least every six months if not more frequently, many functions are fundamentally under resourced creating situations where many employees are essentially set up to fail. While general attitudes towards work/life balance are good, resource constraints make the real practice of work/life balance nearly impossible for many teams. My dept. had a serious "butts in seats" mentality. Apparently, if they can't see you - you can't possibly be working productively.