Back several years ago in the days of LTspice IV, MacOS was the premier platform for LTspice, and Mr. Engelhard, the force behind LTspice, used it as his preference. There were some clever optimizations done to exploit the OS facilities and in general, it was "the" version with the Windows version being the afterthought. I guess it's just changed with the new LTspice XVII. It might have also had something to do with Analog digesting Linear - not up on the details, but the MacOS version was not always the laggard until recently.
FWIW, I use both. I have a fast i7 desktop with powerful fans that I can let cook indefinitely to try to brute force converge something, and I also use the MacOS version on a MacBook Pro laptop when I travel, I fully expect both versions to work well, and in general, they do work well. There are some features that are missing from MacOS, and things like the file structure have been hidden inside of the MacOS "bundle" mechanism for years (but still accessible if you open the bundle), but overall, it's not significantly hobbled - I get good work done on both versions all day long.
FWIW, I have VMware Fusion on this laptop, so I could run the Windows version, but I choose not to - there's really little reason. So sure, it might be frustrating now and then, but the only thing I lament (that I can work around) is the inability to have a "Plot Defs" file where I can define functions to do a Tian probe easier. But, you can just enter the huge Tian probe expression manually (cut and paste) and it works - I have not been shut out of any feature 100%.
I am grateful that there are both versions, and I use them both, these days more than 40 hours a week, so I find them to be essential tools. Sure, a few things could be nicer on MacOS, but that's what we have now...
FWIW, TI also offers TinaTI, which I also use, especially when I have to deal with an encrypted TI model, and they now have a new version of Pspice, which I have yet to try out. So, there are some options out there, and yet still, I use the MacOS LTspice XVII probably the most of all.