For the wagyu served as a steak, have you tried A5 like you had at the sushi places? I've never had much luck in finding American or Australian wagyu that is a significant enough step up over regular Prime to make it worth the price, but real A5 or BMS9+ I've absolutely found to be special.
I haven't found the price difference on Kobe to be worth it over Kagoshima or Miyazaki, though.
Edit: I see this is answered in another comment :)
Are you referring to American/Australian wagyu as "wagyu" ? Did you get it at a restaurant or make it yourself?
I find that American/Australian wagyu is not like Japanese wagyu, but it is still extremely good - it's just a really really good 'regular' steak. It's going to be beefier than a Japanese wagyu with less marbling.
I'd be really surprised to hear that you can't tell the difference between a 'regular' steak and Japanese A5 though. They're really, really different - the marbling is extreme by comparison.
Oh gotcha, yeah I don't really know. I've only ever prepared it myself and I've only eaten A4 (once) or A5. Wagyu is definitely broader and therefor a more abusable term, but I haven't had issues since I order it directly and prepare it personally.
I do, however, definitely eat whole ribeyes of A5 lol
(I've had A5 prepared at sushi places, and that I get, but it's a totally different preparation).