zer0Soul, depends on your interest I suppose, but I'd suggest you rent it first or borrow from friend. IMHO, the gameplay of the DW series is...for lack of better word, crap. It might entertain you for 10-20 hours and then it's repetitive and boring as heck. You continue to use the [][][]/\/\/\ combos to death and that is about it.
I "like" this series because I'm obessed with anything that has to do with the Three Kingdom period, but the Koei has let me down. As far as I'm concerned, DW3 == DW4 == DW5 so if you really are going to buy, I'd say get the latest, as it has more stuff, like characters. Most likely they'll release "expansion" later though, which is another thing I don't like about Koei, expansion that do not expand much.
om3gablue, I highly doubt there will be an English version. If you haven't heard, this game incorporates a highly obnoxious "authorization system". IIRC, the game checks with the server every time you pass a level, save, or load. So for the game to be released in the US, they either have to put Servers for that or take the checking stuff out; either way it's dubious.