Having been to BGW over 100 times, and BGT 5 times. I conclude that BGW is much better. I find the theme of a European area much more enjoyable than an African themed area. BGW has 5 Amazing coasters, I enjoy them all. Apollo's Chariot is my favorite, LNM is simply just an amazing classic( Still fun!) Alpengeist is better than Montu simply because it really is a beautiful area in which you ride through,Sheikra and Griffon are pretty much the same. Verbolten completes something never done at BGT, A highly themed coaster, and an amazing one at that. Darkastle is an amazing dark ride, comparable to a few of Disney's dark rides. Their Water rides are awesome. Escape from Pompeii is a highly themed ride and is still fun, and Le Scoot De Flume is a piece of History.
And to cap it off, the food and shows are MUCH better at BGW.
Now, If you wanna compare HOS at BGT Versus HOS at BGW, that's a different story