I have 2 particolours now but my first 2 Cockers were a gold boy and a black boy. They were both delightful.
Golden boy Josh was cheeky, exuberant and very affectionate. The worst you could say about him was that he didn't like giving toys back to me and would walk away (not a guarding issue, he just wasn't good at sharing)

. He was a very confident dog with people and very skilful at avoiding trouble with any pushy dogs that we met.
My black Cocker Sam was a gentle soul. Very cuddly with people he knew but a bit shy with strangers. Josh loved everyone but sweet Sam loved those he knew and gave his heart to me.
The only reason I now have particolours instead of solids is that I fancied a change of colour. Nothing at all to do with temperament.