If you have science background...ie if you have done engineering in undergrad then Gre will be easier for you. In that case, Maths wont be a problem, but will have to memorize around 4000 words for your english.

In GMAT, you dont have to memorize the words. And all the questions will be analytical. 

Barrons is a good book for both. And for GRE read the Big Book.