Ok, well, I did the whole trip w/ Windows Defender Offline Beta. Keep in mind I (already) use MSE.
1. Since I was just doing this out of curiousity & to be informed, I chose Quick Scan, rather than wait through a Full Scan.
2. Even though I reckon my machine was/is clean, I wanted to see it this would say differently
3. It found nothing.
4. On the surface, I (can) see no difference between this and the appearance or actions of (my) MSE and its scanner.
5. It would seem (to me) it is for ppl who do not have MSE or Defender.
Now, Cat...
"But the version (of Defender) that Windows Developer Preview has doesn't even resemble the old, it looks more like MSE with a facelift."
Defender, prior to Windows 8 was stickly Anti-Malware. In Windows 8, Defender IS MSE or it's MSE but, now named Defender
"MSE requires no learning curve, except to keep it updated & ran regularly."
The 1st part is true but, even, moreso, to the extent that it is fully automated... it keeps itself updated & runs by itself. By default MSE is protecting constantly... it's scan, by default, runs a Quick Scan (Automatically) weekly @ 3 AM. This can be changed run Daily and the scan changed to Full.
In Win8 Defender offers real-time protection, against all types of threats. Definitions are updated automatically. The scan runs Daily, by default @ 3AM... the time (hour of the day) it runs is selectable.
And, actually, Gates has been trying/wanting to offer FREE security out-of-the-box for a long time. And, yes, the obstacle was pay-for-them things like Norton, et al. But, started w/ Defender, then there was OneCare & PC Safety Scanner. But, the aim, from the onset, was what we now see in Windows 8... embedded, free, full package security. As an IT Pro & MS Partner I recall years ago @ conferences it being discussed that this was the goal, asap. Also, that it be unobstusive & automated, demanding little from End Users & system resources. Back then we learned it started w/ Defender which, was not designed by MS. It was from another company called Giant Company Software Inc. MS liked the product, Giant Anti-Spyware so much they just simply bought Giant in December of 2004. Initially it was called Microsoft Anti-Spyware & later was rebranded as Windows Defender. Things evolved into MSE. Now, in Win8, MSE has the label of Defender & Gates has done what he had wanted, in the 1st place, long ago... GOOD, FREE security, embedded & on by default.
Drew