I'd say it's as safe as any other website. They're a large computer company with a good reputation, so I can't see anything going particularly wrong.
If you're worried, just take screenshots of each page (or video it if you're really worried) and keep dated copies of any confirmation bills/letters they send you. If there is a problem, you can use these to bully them into sorting it out for you (not that I'd imagine there would be at all - these guys work with a lot of big games companies such as Blizzard, so I doubt they'd be cowboys.)
If you're really that worried you could buy from newegg?
Hope it all goes ok