Vyvanse is like long acting adderall that cannot be crushed and snorted. Must be metabolized in your digestion to become active.
If you’re a slow metaboliser you end up getting a big overlap around 3hours in which can be quite unpleasant, hence the non XR compound
I had similar issues with XR methylphenidate and Dex, but concerta and vyvanse were find if I took them first thing.
I suspect a bit insignificant amount of people are slow metabolisers and are having a shit run with stimulants as a result
At least for me, Vyvanse is much more tolerable than Adderall XR.