Definitely worth the money.   As with the Apollo equivalent, it spectacularly expands the range of hairstyles available.   I think that applying the fixes is often a two-stage process:  first apply the hair as though for V3/A3/the other one, then apply the Netherworks magnets to get the Miki 2 fit.

Some additional tweaking may be necessary and I have had a few problems when trying to fit complex hairstyles.   The advantages enormously outweigh the limitations, however.