Pros
As a company overall, Covidien takes good care of their employees. Their benefits compare well with other big corporations. A nice additional perk is summer hours (half day off every Friday during the summer). Having worked for many of the business units within Covidien, the culture within the Midwest and Eastern locations compare favorably to the California locations.
Cons
As with any company, your experience will depend heavily on the group you are in. In general, I enjoyed the culture in the Plymouth, MN and Mansfield, MA moreso than the Lake Forest, CA location. Covidien is somewhat of a faceless corporation and is primarily interested in shareholder value. If you're not contributing at par, expect to be cut fairly efficiently. From what I've seen, don't relax and kick back!