Russell,
I have a BX22. You can fit either a 48", 54", or the 60" MMM. I've had the 54" & for 7 yrs & put about 200 Hrs on it. Not any significant problems until last yr. My son ran one of the wheels into a rock & bent the body & the wheel shaft. Now he shaft is frozen in place. WE will be fixing it before mowing season starts.