Pretty slow IMO (though would be faster if you'd replace HDD -> SDD). I've dealt with hundreds of T40/X200/W500 -> T430/X230/W530 or so.
Depends which exact model.
Lenovo has pretty good/long driver support and sturdy cases, but that's about it (with a high price).
How old are the Windows installations (when have you installed Windows)? The age (more older updates) might affect to it too.
Mine cleaned something around 2-3GB (Win7 SP1 64bit).
I've been using this without problems:
[Windows SCM Logs*]
LangSecRef=3025
Detect=HKCU\Software\Microsoft\Windows
Default=False
FileKey1=%WinDir%\System32\LogFiles\Scm|*.*
Wouldn't
[Windows SCM Logs*]
LangSecRef=3025
Detect=HKCU\Software\Microsoft\Windows
Default=False
FileKey1=%WinDir%\System32\LogFiles\Scm|*.*
ExcludeKey1=FILE|%WinDir%\System32\LogFiles\Scm|*.EVM*
work also (don't have to list all the numbers)?
I don't really have any recommendations, but I've been looking for 2TB USB3 2.5" external HDDs and I'll probably buy WD My Passport Ultra, My Passport or Elements Portable.