I was looking for one for a while but had not looked since I got the Impulse AQ.
The cs4pi has gotten good press by some pretty good detectorists on a different forum.
I just went looking on eBay and am not seeing it. If it is still there for a good price, I say get it.
Edited to add: I changed the search and see it; shipping from a dealer in the UK. They had been out of production but today the C Scope web page says to call before ordering because all items have long lead times ... I'd suggest hitting the "contact the seller" link and asking if the dealer actually has it in stock ready for shipping and what warranty. On their web page they are showing that they have them:
C-Scope, metal detectors, Boxed, Bargain, Discounted, Budget, "Machine only"