I think their bass is remarkable. I don't have an MH1C but I can say the 7550 bass hits hard, extends well and has good resolution. Compared to good BA IEMs like the heir 4ai, the bass impact is at another level. It has more in common with the excellent tralucent 1plus2 bass (not quite as tight as the 1plus2) than other, lesser IEMs.
I agree the MDR-7550 does have some nice bass. It has good quality and quantity. Not as controlled as the EX1000 but I prefer it more due to the quantity and listenable sound :). Very good value for the money.