I received a Spin Clean at Christmas. I've done two batches of cleaning since then following the instructions in the box. I heard no difference on records that I'd bought new, but I did hear some improvement on records I'd bought used and those I'd "ínherited" from others. I habitually use a Decca brush on the record before playing, so maybe my new records haven't accumulated much debris.
As for static, the drying process adds static: I can see hairs or fibres attach themselves to the record after it's been wiped dry. I haven't tried air drying. I use a Zerostat sometimes (more regularly now) and I can hear the difference that it makes.
I enjoy listening to my records, but I wouldn't consider myself a sophisticated listener. I'm sure others would hear features I don't (or can't -- my ears are 65 years old ;-) ).
I'll continue to use the Spin Clean on my used and inherited records, but I may not use it on the records I bought new.