Hello from an OTSAV user

Welcome to the forums!

As for PC: Go Mac, there is a reason why everyone uses them in the music industry. It just works.

As for controller:
The VCI-300 is the only real DJ controller you have in that lineup that makes sense. The RMX is a toy, the NanoKontrol is much better for producing in Ableton, the Quneo is good as an addon but I hated to use it alone and the sound card is decent for production but a hassle to use for DJing.