I'm excited to try out this new game for linux. For quite some time I've been disappointed in the fact that developers are not making games to run natively on linux, so this should be a refreshing change and perhaps help to start shifting the views of other game developers.
I bought Quake 4 and Quake Wars: Enemy Territory almost entirely because they ran natively on Linux. When I was toying with the idea of a mod, I used UT2004 solely because it worked in Linux (instead of the new HL2). I even played a month or two of EVE because they supposedly had good Linux support (although it's not native--uses wine).
I would love to beta Heroes of Newerth, if I can still get a key.