I posted this in another forum, but thought I'd repost it here because the information may be relevant to some/all of you. In terms of availability in Australia, 17th of March is the latest date for the new shipment. I was lucky to get mine about three weeks about but they promptly went out of stock.
Below is my post regarding an issue I've had with the G-Force version of the drive, I'm now awaiting stock of the non G-Force version.
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Hi,
I'm yet to find anyone with this same issue, but I'll share it just so someone doesn't have the same troubleshooting hassle I did.
A couple of weeks ago I got a Seagate 7200.4 500GB 7200rpm drive (G-Force version) in anticipation of my UMBP 17 inch. In the meantime though I thought I'd install it in my 15inch UMBP. I did this at work and just did a straight mirror (not using Migration assistant, which usually works) to the new drive. I then installed it into my laptop. For the first hour or so it worked, but then completely froze, just the rainbow wheel going around. I turned it off and back on several times, each time freezing within three minutes of startup.
That evening I came home and it appeared to be fine, but I thought I'd run a recovery and then use the migration assistant to bring across everything instead of a straight mirror. This worked and I used my computer for the entire next day from home with no issue.
Next day went back into the office and exactly the same problem, freezing within three minutes. I unplugged all accessories from it, left it up on it's little stand (so it's level with my LED cinema display) to see if removing all the cables solved the problem. No, it didn't.
Might I note, that by putting in my old hard drive everything worked as it should at home and at work.
After then reloading to the 500GB completely from scratch, re-installing apps etc. it again worked at home, no problem. Took it into work, freezing again, without even being plugged in.
it then dawned on me that the only thing that was different between home and work was that at work I have it up on a stand (
http://www.raindesigninc.com/mstand.html) which keeps the laptop on a tilt of about 40 degrees. I took my laptop off this stand and sat it flat on my desk and voila! it worked perfectly.
So it would seem that this hard drive will freeze after 3 minutes or so if it's running on an angle of about 40 or 45 degrees. Now I'm not sure if this is a completely faulty drive, or something to do with the G-Force feature but in any event I've ordered the non G-Force drive to replace it. Until then I'll just keep it on a level surface.
Apologies for the long post, but if it saves one person having to reload their computer three times and waste hours of their time.
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Now:

Mac Pro 8-core 2.8GHz/10GB/4.5TB/2x 23in ACD

UMBP 15 inch 2.8GHz/4GB/500GB
Coming:

UMBP 17 inch 2.93GHz/8GB/500GB+500GB (MCE Tech OptiBay)/Glossy