Pros
Great hours, family-friendly. Working from home is normal. Late nights are extremely rare. There are a lot of smart people. Good health benefits, 401-K matching, and vacation. I worked in professional promotions, in the Worldwide Plaza offices, which is fire-walled from both CME and the Medscape/content creation side. This is a 3rd party advertorial shop. The technology and in particular digital subscriber list is what the company is selling-- not content.
Cons
For creatives, particularly if you are coming from an agency as a copy or medical affairs person, the hours are great, but there is little to no opportunity to actually make an impact on the brands you're working with. For a writer or designer, this can be frustrating. There is a LOT of cutting and pasting of agency-created content into templates. The real creative work at a company like this is in product development, which takes place elsewhere. Also, the stock price is at the heart of everything. Management has been known to "purge" more senior, higher paid folks, and then bring in recent college grads after 6-months or so. However, if you're good with your boss, you will be spared, generally. Don't expect big raises. Just plug away and don't make too many enemies. There is not much urgency to the work. Not a great place to gain digital experience, surprisingly, since so much of what you learn is applicable only to WebMD, not elsewhere.