Hi Mike,
Its been way too long since I heard a pair of MK1's and with totally different kit,so I am not able to offer a "fair" evaluation between MK1 and 2.
But,a little background info may be useful.
The MK1 had the "fluting/Chamfering" on the front running all the way top to bottom.I seem to remember that Rega decided to change this for structural integriry reasons....(?)
The MK2 effectivly came in two versions,both had the fluting on the top half of the cabinet only,the earlier versions had centre-offset tweeters,the later versions were symetrical.
I believe that,on the MK2's the drive units and internal electronics were exactly the same and that the changes were effectivly cosmetic. (possibly something to do with the availability of the speaker carcus? )
It would possibly be better to understand the MK2 as Mk2 versions "A" and "B".
Around the same time as the change between MK2 A & B there was a change from a three point stand to a Four point stand.(customer requests ?)
I myself have a pair of the MK2 "A" and "Andy H" who lives eight doors away from me has the MK2 "B"
I can discern no differences,(or so very little as not to matter to me) their sonic "signatures" seem pretty much identical.
They are perhaps a little "lean",but VERY FAST and agile and revealing....I think that they are excellent speakers and like them LOTS !
To the best of my knowledge,the above is correct,but I am prepared to be corrected !
...You could always try ringing REGA themselfs,if you do,please can you correct any of the above that I have got wrong.( I do like to know these things)
Regards
Chris