I actually much prefer the Beyond Burger. Maybe it was cooked wrong, but the Impossible Burger I tried tasted a lot like a Morningstar Farm's Griller's Prime to me. Not a bad flavor mind you, just not worth the $3 surcharge.
Agreed, I think the way its prepared definitely matters.
For me, I think the Impossible Burger seems "better" because I've only had it prepared by restaurants whereas the Beyond Burger I've mostly made myself from the grocery store.