I like the hard one, especially if you want to keep edges sharp.
But I have a medium on the Rotex as well and a soft on the ETS, there is a reason they make these, they fit different purposes.
So think about what you‘ll most likely need to do and take it from there.
If you do not require the new and improved Jetstream 2, there are currently a lot of good prices for the last version on eBay, at least here in Germany..