GMAT or GRE for technical schools

To help you decide, maybe you can take free mock test of both GRE and GMAT. You can then find out which test matches your current skill set better and which test requires more preparation time.

In my view:
GRE: Quant is slightly easier than GMAT. To illustrate, I should be able to get perfect 170 on GRE. But I do not think that I can hit 51 on GMAT yet.
GRE: Verbal does require significant investment on vocabulary especially if English is not your native language. That said, those advanced words are indeed very useful in graduate study.
GRE: Reading comprehension is slightly more challenging than GMAT partly because of the vocabulary used and partly because of the topics chosen.

GMAT: SC is unique. Difficult SC questions can be both time-consuming and frustrating.
GMAT: CR accounts for roughly 1/3 verbal questions. Challenging CR questions are more difficult than their GRE counterparts.
GMAT: Vocabulary is at medium level.

So, it is extremely difficult to get 800 in GMAT. On the other hand, it is relatively easier to hit perfect 170+170 on GRE.

PS. GMAT AWA is much easier than GRE AWA. (For example, I received 6.0 in GMAT AWA but only 4.5 in GRE AWA. Percentagewise, though, my two scores are comparable.)
PPS. GMAT also has a unique IR section.