I haven't used the service myself (I'm still waiting for an invite), but I look forward to a new entrant in this niche.
The name might not sound like much but the service has at least a few features to recommend it. It supports full-text search, lets readers sort by metadata, and it can extract the cover images and show them when you browse your library. Best of all, PBS supports the OPDS standard, meaning that the service can be integrated into reading apps like Aldiko, Marvin, and more.
I don't know how much NeoLibrary will cost, but Personal Book Space costs $10 euros a year for up to 5GB of space. That is considerably more expensive than Google Drive, which gives away the first 15GB free, but does Google Drive (or its competitors) offer the same features?
More to the point, do you know of any similar services?