Also a Mac user for the last 10 or so years, so I know Logic really well, and have invested quite a bit of money in hardware & mac compatible sample packs over the years.
Which used to be just fine, but the way Apple is going these days, I do wonder if I'll jump ship when my current rig finally dies. New Macs are non-upgradeable. And so expensive. If I'm going to spend good money on a computer, I want to be able to upgrade/ replace parts easily and by myself without giving Apple more silly money to either do it for me or replace the entire machine.
So I'd probably get a windows rig and run pro tools/ cubase. Running a current hackintosh isn't going to be an option within a couple of years either as Apple are developing their own proprietary chipset.
A friend of mine says that linux support for vst's and such is getting better all the time so I may look into that when the time comes. I'm running linux for everything else non-musical anyway.
As for collabs, I don't think platform really matters. So long as you know how to export midi, or stems, and the other person has important project info such as tempo and time signature, you can collaborate with someone running analogue gear if you want to