Bitcoin Investment

Hello there Fellow Forum Members, I was wondering if I can have some opinions on making some investments in some Bitcoin "Mining" Machinery. I know the currency rate is vastly rising but at the same time declining very fast. Was at about $1,100 USD per Bitcoin mid-way through November 2013 and now is at roughly 800 (February 5, 2014). But as the Currency goes up the "Arithmetic" problems are getting bigger, longer and harder to solve. And any good "Pool" (Bitcoin Mining Group(s)) that are a good idea to join. And Bitcoin or Litecoin?

-Thank you