I've never had the opportunity yet to put my fingers on a 8-string guitar, but I hope that one day I can have something like this Brooklyn Gear GB8. It must be like playing with the thunder! I guess that it's not a guitar you should play like a regular one - with just a lower and a higher string. I'd rather use it in open tuning in a modal scale like a zither or something.
This one is nice because it doesn't look like another pointy superstrat like ESP's or Ibanez's, since - and it's a pity - over 6-string you're supposed to play metal.