The oldest sushi chef at my restaurant retired a few weeks ago.
He would buy new Suisin Hayate 270's every few years when his wife didn't complain too much.
I now have his old ones ground down to 240, and another all the way to 210. Lucky for me I only paid old Kazu 50$ each.
I'm still learning about sharpening...but once the money is taken out of the equation...I just have a well made, straight, flat blade...and I guess its better to learn on that.. then one with flaws that make sharpening confusing to a new guy like me.