Gamershare went out of business in mid 2007 (not surprising as it was our lowest-ranked site); this review is kept up for posterity's sake.
Gamershare is not a regular game rental site, instead it is a peer-to-peer (P2P) game trading community. Members can legally trade their games with no limits. However, it is still in beta testing and probably doesn't have a large enough user base as yet to support a wide range of titles and trades. It may be something to watch for the future though, the Peerflix of the game rental industry.
Of course, the main problem with P2P trading services like this are there are plenty of people willing to trade old titles, but very few wilLing to part with new ones (which can simply be sold on for a good amount on ebay). So competition for the few recent releases up for trade will be tight; to decide who gets them, games are matched based on predefined selection criteria such as geographic proximity, queue wait times, and other factors, desgined to get a game to the destination as quickly as possible.
There are plenty of features, like you can suspend your account when on vacation, rate games, get recommendations from their preference system etc. Nonetheless, until the system matures with enough people participating and gets beyond beta testing, we'd steer clear.
Prices: Gamershare doesn't have regular, monthly tariffs, but they do have two types of fees, for "GameTrades"--when you receive a video game from other members you pay $2.99 (which includes postage), generally billed monthly or after a spefici amount of trades. Also, if you have enough "GamePoints" you can request a video game; these points can only be earned by trading video games, or purchasing the points outright. They do apparently award GamePoints based on the availability, used retail cash value, and release date to encourage trading of new releases, but we still believe there will be trading shortages on those titles.