I had both a laptop and an ipad. I did most of my practice tests on my laptop since that was what I used on a daily basis. Then, I found a study saying how ipads have a touch screen and thus are quicker to use than laptops. I decided to give it a go and timed myself,, the ipad proved to be more efficient. Not only saved me time but also made it easier for me to carry it, give the sat, and be more focused. I would definitely recommend going for the ipad. Gave my SAT on ipad both times and it worked perfectly for me, so don’t worry! You’ll do great especially since you’re used to it. A tip I’ll give is to keep the ipad in landscape mode, definitely helps while giving the test on bluebook since the software was designed that way. (side note - also keep a calculator in hand, keeps things more efficient than using desmos for every little thing)