Once you subscribe to OnLive, you also have the option to play from your PC and many mobile devices where the OnLive app is available. The service also has features that let you be a spectator, which is always a good way to take a sneak peak at a game without being an active participant.
In the meantime, OnLive rival Gaikai (now owned by Sony) has partnered with Samsung, and you can expect it to show up in Sony BRAVIA TVs as well. Cloud gaming has been the object of tremendous hype, and has been often hailed as a next-gen console “killer” (which it is not, at least not yet).
Replacing consoles will be a long road, as there are difficult infrastructure and licensing problems to solve. Because of that, the viability of that business has yet to be proven, and OnLive is a prime example of this. Despite being the most successful on the market, it ran into financial troubles and had to go through major structural changes recently.