Meh, I dont see the point in "renting" a game. Granted the Beta's are usually free, but then again, its not a finished/polished final game, so again, what's the point? The only "MMO" game I play anymore is Guildwars, mostly because it doesnt cost me anything to play beyond the initial purchase. That and it really is a well made and fun game.
AoC just looks like another attempt at making money off of an MMO that will "try" to be the next WoW. I personally despise WoW, but I respect the fact that it has been as popular as its been. The problems I see with AoC is that Conan the Barbarian wasnt that interesting of a premise in the first place. It pales in comparison to LotR and DnD. The combat is going to be same ole same ole MMORPG 123repeat button timing and then sitting around waiting for energy/health to recharge. In an RTS, thats fine because there is other things to do, other units to control. In the RPG world, its a single (or sometimes a small group) avatar with just alot of wasted time.
IMO, it just seems "gimicky" in order to allure those with short attention spans into spending their money in the "latest and greatest" new thing. If I am to get into a new game, it will be months after release and user review pendings in order to decide if I am to part with my cash and time or not. (Although in the rare case of Sins, I bought it upon release, but that was still after reading many many reviews).