I've had my experieces with "cheaters" and the biggest of mouthpieces. I was introduced to a Marcinkewitz mouthpiece (Bobby Shew Model) about five years ago. At first, I thought it was a gift from beyond. I couldn't get enough of it. I was scolded by my peers for using a "cheater." I was lead in the jazz ensemble and screaming every time I had the chance. My range went higher, my tone stayed the same.
Then I got into college, and had no use for it. So I stuck to my Bach 1 and a Bach 3C. Then I spent a summer with Phantom Regiment for the summer of 2002. Pete Bond, our caption head, wanted to open up the bores and the throats to our m'pce. So I gave him my 3C. WOW!!! My tone was as open as the sky. I retained the range I had, or I never tried to increase or test to see if it went beyond what I could play. When I was back at home on my B-flat, I did my normal work-out. Then at marching band practice, while working on "Big Noise from Winnetka," I tried out the range. I went from a Double A to the Double C# on my open 3C. A Major 3rd higher. No "cheater." Just long tones, lip slurs, etc. And I'm still working on going higher.
So, I would have to say that using a "cheater" mouthpiece is all up to the player. But to quote previous posts, it's a matter of personal preference. AND, long tones and lip slurs are the best thing to play into the stratosphere. My personal preference is my 3C. Your preference may be a Schilke 6A4a, Bach 1, Wick 2W, etc. It's all up to you. Besides, I hate the name "cheater mouthpiece," I perfer "lead mouthpiece."