The Answers forum is a peer-to-peer type forum of users of Microsoft products so I doubt if you'll be able to get Microsoft's official position or view on UniBlue.
With that said, I highly discourge the use of any type of registry cleaner or optimizer, whether free or a commercial product. I'm not saying they'll cause problems in every case, but a program that blindly removes entries from the registry based on a predifined
set of rules (without knowing the system's actual configuration) will eventually cause issues, in my opinion. As to removing unused orphaned registry keys to increase performance, I once read it was the equivalent to cleaning a dozen or so parking spaces in
a parking lot the size of Montana!
Here a few links for further reading:
Is it advisable to use Uniblue Registry Booster?(see Ken Blake's (Microsoft MVP) post for additional info and links)
http://answers.microsoft.com/en-us/windows/forum/windows_7-performance/is-it-advisable-to-use-uniblue-registry-booster/b40f0fc8-442b-4352-b427-860c2c29091b
Clean Registry(see Shenan Stanley's post)
http://answers.microsoft.com/en-us/windows/forum/windows_xp-performance/clean-registry/8b24dd45-d2d1-4c9b-8e88-d173321ea13f
Don’t pay for software you don’t need — Part 2(see Some Registry cleaners do more harm than good)
http://windowssecrets.com/top-story/dont-pay-for-software-you-dont-need-part-2/
AUMHA Discussion: Should I Use a Registry Cleaner? http://aumha.net/viewtopic.php?t=28099
Regards,