if simplify 3d works on windows 10 so will the printer.

Well to start with you can save money by buying the qidi - same machine, just cheaper.
And yes they are all open filament, much much cheaper.
Pretty sure plenty of people are using replicator clones on 10.

Never heard anything that good about the davinci - so would presume that the rep pro would be the better machine.

But also bear in mind for that kind of money you can get some really serious machines in 'semi-kit' form.