Just to add to the above posts, drilling out the hole is supposedly required / better if you’re running a rimstrip. It just allows the valve from the rimstrip to sit deeper in the rim and that seals better apparently. Now, since a rimstrip isn’t required with the Stans Flows (Yellow tape works perfectly) you don’t need to drill anything.
I bought the flow rims for trying out tubeless and I have no problems recommending them in terms of ease of fitting etc, all very straightforward eventually, despite a lot of confusing waffle on the internets. However I’ve not had them long enough to comment on durability, time will tell.