I'm testing the beta for my workflow - I'm an Illustrator/CutStudio/RolandGX-500 cutter user, and it's very impressive. Challenges I've come across so far are the amount of points generated when an line/object is outlined, and CutStudio which currently doesn't accept Designer eps/svg files.
First issue, my cutter has a point limit - in Illustrator you can use the Simplify tool (I find it inaccurate and fiddly) to take points away - if you can do this in preferences or setup I've not found it. I haven't found a workaround for this in the Designer beta yet, so apologies if it exists (I suspect not, as I've only ever come across the need to do this when working with a cutter), plus, more modern cutters may not have this issue (any expert advice out there?)
Secondly, I've approached Roland as a customer asking them to modify/create cutting software that will work with Designer files, and I encourage anyone considering using Designer in this way to do the same with their suppliers - there has to be a better way and if the price is right, Designer is looking like a very fine replacement for Illustrator indeed.
Well done Affinity! Nearly there...