My advice:
Read the rules, it something like Candidate Agreement or similar. I could not find anything like it on Prometric's website yesterday, but apparently its mentioned in a letter I never got, and is available through a search of the words used to describe the agreement. It may have come up while I signed up, but I didn't see it. I sure couldn't find it looking later, and thats exactly what I was looking for.
There are lockers available, you will need to use them. You can take your id, your reference materials (one box only), the locker key, and thats pretty much it. Forget your wallet, purse, car keys, jacket, etc. That was my experience. Yours may vary. There was a booklet issued, with sketches related to problems in the exam but they're not numbered. I would write down the number, for future reference. The computer was only a slight hurdle, but still a little frustrating. It takes a few seconds sometimes to load problems, but generally pretty quick. You can only go forward and back one by one, until you get through the entire exam and only then can you click on a specific number on a list at the final screen. There, it lists problems you marked, and ones you didn't answer, and ones you did. You can review just marked problems, so keep that in mind. This is all shown to you prior to the exam, so once you review how it operates it should be a no brainer. I can't really complain about the computer, it was really a non-issue IMO.
What I didn't like?
The desk is small. Not much working space.
Sometimes drawing sketches for myself I can't stand not having a straightedge. You can't have one.
I read that if you brought a jacket, you had to wear it at all times, or put it in the locker. I was not allowed to bring one at all, was told it was too big/bulky. Lies, as far as I am concerned.
The average room temp was ok where I was, but getting blasted with cold air every 10-15 minutes was no fun. That's why I brought my jacket.
They have, IMO, stupid rules. They are also not well informed of them, so probably best to leave them with nothing they can take issue with.
No watch or other timekeeping device... unless your calc does it. Sure the computer has a countdown clock, but what if it crashes? You have no way of knowing anything in regards to time.
I did get a couple old pencils (not mechanical) with little eraser left. You turn these in when you leave.
I would expect time to be a factor, just like the paper test. I can't say if this was worse or better in that regard, my initial thought is... if anything, its not much.
Any questions, feel free to ask.