The next version of MacOS will will not allow the editing of UserForms in Excel so I've installed a virtual machine (Parallels) with the current MacOS which I will not update when the new version comes out. I can currently run all of my excel spreadsheets (Excel for Mac 2011) using this (they all run flawlessly) and will be able to update my main OS to the new version.
Actually, I have installed all of my 32 bit applications on the virtual machine.
This a lot cheaper than buying a dedicated Windows computer.
Now I have all the benefits - two computers in one with all the advantages of both.
(I have no form of business association with Parallels.)