I used to own a F135+ and now have a non-plus. If you're happy using the relatively basic interface of the TLXclient software, there's no particular reason to pay the extra for the plus. Make sure you download and read about all the available scripts for TLX on the Facebook page. They make using the software a whole lot better. There are scripts which enable keyboard shortcuts, maximise the screen, enable B&W scanning etc. The essential script is 'TLX: Scan Positive, B&W, 16 Base', which enables 3000 x 2000 mode so the output matches the plus version.
I've noticed my non-plus runs a little slower than the plus...or seems to. I reckon it takes about 8 minutes to scan a full 36 frame roll whereas the F135+ took maybe 6 minutes. Hardly slow either way and not a big deal...unless you're running a minilab and processing 300 rolls a day!
I use VMWare on my Mac for both units. I tried using an old Toshiba laptop with XP installed but it point blank refused to recognise the Pakon. Using the VM is seamless.
Personally, I think the Pakons are essential if you shoot 35mm film and want to digitise it (and can't justify a Frontier/Noritsu).
Someone recently noted on Facebook that the Pakon unit retailed for $15,000 when new. Someone else asked if that was for the entire mini-lab, but apparently that was just the Pakon itself. I'm not sure how accurate this is, but either way you have an amazing, pro scanner on your hands. Excellent purchase. Have fun with it 🙂