GMAT Strategy

In school I would do substantially better if I got a second run at something, do you think I should do a "practice" GMAT, cancel the score, finish prep, do the real GMAT?

If you do the GMAT (cancel or not) does it tell you which questions you got wrong or otherwise give you a chance to learn from it? Otherwise I think just being more comfortable the second time is still a perk

I heard some nefarious writers have written a "practice" test with a different address or something so that it wouldn't count.

GMAT Prep exams give you two "practice" GMATS :!:

This alternative is a lot cheaper. Plus if you cancel your score , you're never truly going to know what level of questions you were getting.

if you choose to go with the real exam and use the score as your benchmark I would not cancel the score

my reasoning is most schools do not take into account your previous scores, and if you do choose to use is as a benchmark then you want to know the score right? or you will not know if you improved in your studies or not

I heard some nefarious writers have written a "practice" test with a different address or something so that it wouldn't count.

I don't that's possible. They take finger prints at the test center (some test centers have started doing retina scans) and you need to show a passport. There is no way you can fake who you are in order to do a "practice" test without having the score on record.

GMAT prep is A MUCH better choice of doing ^practice test^.

Reasons:
The Graphical user interface is same to real GMAT so you'd have almost the real experience
it's cheaper, oh it's free.
you can see which questions you answered wrong & which ones correctly.
ie. you can analyse your performance after the test
your 'mock' score will remain secret.
In real GMAT you cannot see final score before(/if) you decide to cancel the test.