While the SW grip variations has become the de facto standard in pro tennis it is not necessarily the best all around grip for you. Elite such as Federer, Dimitrov and Del Potro use an Eastern (or a modified Eastern). Quite a few WTA players use it as well. With non-elite players, Eastern grip will often work best. No right answer. I depends on the needs and abilities of the individual. Some players, like me, will employ a modified Eastern for most of my shots but I will often switch to a SW for certain situations -- like high balls. Many pros and non-elite players will employ more than 1 Fh grip. But this is not necessarily for everyone.
With his Eastern grip variations, Federer can still hit more topspin than most players. According to the article below, Roger's avg topspin is 2700 rpm compared to 3200 rpm for Rafa, the topspin king. Rafa's heaviest topspin has measured around 4900 pm. Roger is not too far behind with 4500 rpm. This is more than most ppl will achieve with a SW grip.
http://jimfawcette.typepad.com/fnet/2012/02/federer-hits-with-more-spin-than-nadal-.html
Coach Brady Heite does a decent job of discussing the pros and cons of Eastern grips.