Recently I ported my site to Joomla 2.5 and had issues integrating DOCMAN since I had a legacy, non-standard file structure. The developer went overboard in helping me by uploading a new database, advising me on issues, etc. I couldn't have asked for better help. Even though I offered to pay him for his time he declined, saying that it was just part of the support they give to DOCMAN users.
Get this component. You won't be disappointed with either it or the support.