HEPA, automatic starting, quality build are my top 3.
Variable suction is great, but not a deal breaker... I rarely turn mine down.
If I was buying a shop vac today, I'd likely get that hepa Fein vac. Or possibly another Festool vac.
But as had been said, it isn't going to be very effective with your saw or jointer...
I get it, you want to buy something that will get your started and work into the future, and you really do ultimately need a good shop vac. But I'd also be looking at fast-tracking a proper DC purchase with effective filtration/separation soon.
You really do need it, the shop vac won't cut it.