Anyway, The MK1 is a really great synth and im happy to have both right now.
I like using the a4 in polymode so having both is great.
If you have the money i guess the MK2 is worth it for the new workflow which is much improved btw.
The A4 is not an instant gratification synth but with careful programming i like it as much as my OB6 !
Unfortunately the MK2 has some bugs right now but nothing major. Note that using sound lock on the MK2 is a pain in the *ss with the current OS. see this : A4MKII - Sound lock hiding note parameters