I don't think those balls are necessarily that similar. The Bruiser was a solid while the Rampage is a pearl, and the Bruiser core had a lower RG than the Rampage's. The Bruiser should be earlier and smoother than the Rampage.
The SmashR and Nemesis/Wizard, I might see a good comparison. Both dull solid PK18 with medium RGs and diffs. If I had one and wanted something different, I wouldn't get the other. If I wanted to replace a SmashR, the Nemesis/Wizard should be quite comparable. By the numbers, the Nemesis/Wizard are stronger.
SH