I use Sharepoint quite regularly, and I find it kind of slow and all kinds of annoying. If everything is already an Office document AND if you're company is willing to keep everyone's computer up to speed with Office versions, then Sharepoint can work fine. If you've got a variety of Office versions (like we do) then it's far less good. My machine has some older versions of office components and the integration doesn't always work correctly. I've learned to not try to use integration at all.
The most important thing with either solution is to make sure your people know how to use it. We had some problems early on (versions of files with different names instead of using the versioning built into sharepoint) that were really just gaps in people's training.
