I must admit, my C4 is being returned today.
Technically it's a brilliant pedal, but synth on Bass isn't really my thing when I've also got a midi keyboard and Laptop with DAW/Plugins to cover that better. 90% of my use for the C4 is for octave and filter and I like more hardware control - the Spectrum might have been better for me as the 2 control knobs have the 'alt' function.
With either the C4 or Spectrum though I'd still probably be thinking I want at a minimum to have a DMC micro and the EHX CNTL which would put the total price up above £350....that amount will go quite a long way on octave and filter pedals. Less potential variety in some ways but possibly better at doing their niche better with minimum tweaking? And the other C4 things like Tremalo and distortion are covered better by other pedals I've got.
Also, this is perhaps just me but I found myself spending hours hooking up Laptop/Phone and obsessing over fine-tuning, I like doing that with hardware pedals a bit but not to the level of obsessiveness I do with a Laptop hooked up but I can't stop myself, a distraction I don't need!