I've just within the past few months begun to use OO.o 3.2.1
It's not ideal. But it's better than what I used to use.
Is there any compelling reason for me to switch now?

Well there's a bug in OO.o in the auto lists Numbereed and unNumbered, that seems to have been fixed in LibreOffice. Additionally there is a difference between OO.o for Windows and OO.o for Linux (on many distributions) in that the Linux version contains code from the Go-oo fork, and thereby has better support for Microsoft Office Document Formats than the Windows version. This is something that has been happening on a Distribution by Distribution basis, when the distributions compile OO.o, and not something that Sun/Oracle have been doing, which means the Windows version of OO.o offered by Oracle is missing this code.

The LibreOffice versions for Windows and Mac and Linux will all contain the same code base, and will all improve in step, and will contain improvements not available to Oracle, and therefore OO.o, due to copyright assignment issues, where Oracle insist that copyright must be assigned to them for all code submitted. The LibreOffice has no such artificial constraints on what code can be submitted, so is already, and will continue to be better than OO.o.