The Coincidents are an excellent match with Atma-Sphere electronics. An MP-3 or MP-1 preamp is a synergistic match with the MA-1s - the special caps option for the preamp is recommended. I haven't compared either with the CAT preamp so can't comment, but it mates well with a variety of amplifiers with single ended inputs and has a good phono stage. The JL2 amp, as Jafox describes, is quite neutral, and as Strapper211 indicates the bass is one of its strong points. I would suggest auditioning both if possible; you will quickly know which you prefer. Since you appear to be in the UK I'll mention there is an Atma-Sphere dealer there, and I imagine a CAT dealer as well.
Brian
Brian