My prediction is that whichever one you buy, you’ll think you made the right decision. But maybe you should buy what is arguably the best Suzuki, the A-34C, which is bit mellower sounding than the M-37C. Construction quality of the A-34C is comparable to that of the M-37C, but the A-34C is more compact and noticeably lighter. It has three fewer keys, lacking the low F and F# and the high F.
Shipping from Japan to the U.S. is about $40.