As a test I installed Win8 beta into unallocated space to get a SRP. The SRP is 350 MB with 200 MB of used space. The reason it contains more data than the Win7 SRP is because it contains Winre.wim (in a Recovery folder) which is 158 MB.

The SRP is easy to remove.

Dan,

I just checked a Win7/SRP system and winre.wim is in a randomly named folder inside C:\Recovery.   
Winre.wim is 145 MB in size.

Another difference with Win8 is the SRP and the C: drive both contain bootmgr.  With Win7, bootmgr is only in the SRP. So no longer will people see "BOOTMGR is missing" when they restore a Win8 image to a new HD without restoring the SRP. You still get a Windows Boot Manager error screen but it gives specific instructions to boot from the Win8 DVD and click "Repair your computer". It is not quite so easy in practice as there are a few choices to navigate but one repair does enable Win8 to boot. Two repairs aren't needed as with Win7.

My impression of Win8 is similar to yours. I didn't really give the Developer Preview much time as I disabled Metro and used the Start menu. That made it like Win7. You can't do that with the Consumer Preview so I've spent time learning how to manage Metro and it doesn't annoy me anymore. The only program I've installed is Image for Windows and I've mainly been learning where to find things and do minor tweaks. I still can't see improvements from Win7 but maybe later.