JCA is a project mike soldano has personally supervised along with his partner who is in china overseeing production. they are very very good amps, and for the money, nothing touches them.
whether they're up there with an SLO i'm not sure, have yet to try one in the flesh so to speak. i'll maybe nip down to guitar guitar tomorrow and see if they have any in. From what i've been told, they coma as close as a 600 quid amp can come, but they're missing some of the harmonic richness and nuances that sets the SLO apart from everything else