There's a ton of misinformation about Virool floating around these forums. Virool is NOT a botting site. It functions exactly like Google's service except the places they show your stuff are not nearly as good and sometimes they're forced watches like a commercial you can't turn off.
Virool is 100% legit but the views you get will be just that, views. If you paid for 10,000 views, you'd probably get 2 subs out of it and no repeat views because of the way they serve your video (as an ad) to people. But it is legit views and not botting. I tested it out for 1000'ish views. You can track everything that comes in from Virool right in your google analytics and see each source it comes from.
So anyway, definitely go with Google Adwords if you want views that will possibly matter in the long run.