Whitehat is always better than any other method. Whitehat sticks, gets your a lot of visitors and gives you a high PR/respect.
Blackhat works, sometimes sticks but if you get caught you are put to shame by the Search Engines.
You asked which I prefer, not which I do.
I prefer white hat site i'm going for the long term business.
According to me I would do lot of white hat work on Page SEO & in Off Page would carefully use Black Hat ..
I prefer Grayhat
Whitehat is the best method among all the above mention methods,and white hat method is also recommended by all the search engines..!
i prefer Greyhat which will give more shade of White
just use hardly 30% blackhat mix with White so that not get that !