I've got the mono and the stereo. The mono is a great record to own -- great presentation, really strong sense of attack. The stereo is still amazingly cost effective and also very very worth it -- and yes, probably the way that Jimi was trying to blow your mind
I've got the Impex and it is a beautiful sounding record. I don't have a comparison so I've been hesitant to comment -- but it would be very hard for me to justify buying a "better" copy. (Caveat: it isn't my favorite Monk album, but the fact that you might be able to get the SC Monk in Tokyo and the Impex for less than the total...)