Just remember its only for those that are eligible (however I'm sure there are alternative ways of getting around the restriction).
"This offer is only available to eligible students, staff and faculty who possess a valid email address at an educational institution geographically located in Australia. This offer is non-transferable."
I was annoyed when the price jummped up a few days before I got around to buying it. Just about to put a purchase through now.
Offer Duration:
This offer shall continue until terminated by Microsoft.
Microsoft reserves the right to terminate this offer at any time.
EDIT: Some of your comments have reminded me of a few things about the offer (which I knew already, but slipped my mind so I'll now share).
Although its called UPGRADE, it can be used as a CLEAN install. I've done it myself. Instructions aren't hard to find via google.
It was $50 from the time the offer started until the end of March. From April 1 it switched to $119. Now its back to $50 for who knows how long.
Yes, you can purchase multiple licences if you have access to multiple (valid) email addresses. However this does breach the T+C (http://www.microsoft.com/student/discounts/itsnotcheating/te…)
You can pick which install iso you would like (x64 or x86). Or download both. They are roughly 3GB each (give or take 500mb). There is a time limit until the download links disappear however, so make sure you time it right if your quota is tight (which is why I got screwed when the price went up…my internet resets on the 7th of each month).
You do not get the install DVD unless you pay some extra money for it…$16 it seems.
Using the iso you can install via USB (I used Win2Flash to make it install via one of my externals). Installs much faster too, since USB is faster than DVD. I think it was only about 15mins until my Windows install did its first restart.
If I notice any more points in the comments I'll add them here, but I have an exam in the morning so won't be checking too often.
Remember the key works for both 32 and 64. If you can get your hands on the installation for either, download the other one.