Yes, we use Plastic SCM (small team of 5) for 2 years already and it works great and even gets better every update!
Support is very good (within an hour or at least the same day a response!).
Also branching and merging works very good in practice. Every programmer can work on it's own in his own branch (using branch per task pattern). Such a big relief. When you switch to another branch all changes are automatically shelved/stored on the server. When you switch back, the changes are reloaded, which is a really nice feature! You don't have to worry to loose changes, because Plastic handles everything very good.
Without doubt Plastic SCM is the best Version Control System I've ever seen (used MS Sourcesafe, CVS, SVN, StarTeam). Also heard of other's the branch support is much better than MS Team Foundation.
