I owned an SM70 and currently own a pair of the Monarchy SE100Delux's. The SM70 was a sweet little amp. I just sold it but it was hard to let it go. Was looking to buy another one and run them as monos but could not find another one with matching faceplate. The only problem I had with the SM70 was that it ran hot. It doubled as a space heater in my little 10x9 office; good in the winter but not so good in the summer.
Hope this helps,