Not to blow hot air but the folks at Omnigroup make incredibly good products. The synchronization capabilities in Omnifocus 1.5 are truely remarkable. I am not aware of any other software that offers this degree of synchronization.
In regards to this post I have been mucking about with Yojimbo (
http://www.barebones.com/products/yojimbo/), Together (
http://reinventedsoftware.com/together/), Journler (
http://journler.com/), and Eaglefiler (
http://c-command.com/eaglefiler/) for a light weight file organizer however I am underwhelmed with these products simply because they either can't sync (yojimbo/eaglefiler) or their synchronization is poorly executed (Together). For heavy duty file organization you cannot beat Devonthink Pro (can't wait to see Devonthink 2 when released!) but I believe that Omnigroup could do well with a light weight file organizer that employs the sync technologies available in Omnifocus.