I believe semi western is the best balance for most folks. I wouldn't advise a traditional eastern grip to anyone these days even to the tallest folks as the premium on spin these days is quite large. Conversely I find the full western to be a bit unnatural to most people and much more difficult to learn. Plus i don't think the western is good for most amateurs as they already have enough problems with low balls, footwook, etc. Though if you really work hard on it the full western should be just as good. You should also consider what type of game/style you are best suited.
At 6' 0'' and more of an attacking player use a semi-western/modified eastern grip ala federer.