No real-world experience with the SP Tech's, but they look interesting enough to peak interest. Certainly familiar with the midbass driver it incorporates.
As a Dynaudio dealer as well as owner of the C1's in my own personal system, the C1 is near and dear to my heart. When driven by appropriate amplification, there are few monitors or floorstanders for that matter that can better it's imaging and silky highs. They are simply wonderful smooth sounding monitors. If it lacks anything, it would be in bass depth. Personally, I run stereo subs in my system, but many 2-channel purists love them as is.