I have the BK-7 and I think it is a great knife, but the ESEE-6 is also a great knife. Neither are my first choice for choppers, I'd rather use a BK-9, Junglas or Lite Machete. 'As is' the BK-7 is the better value knife, but if you add micarta scales or a kydex sheath to the BK-7 then it is a toss up (BK-7 cheaper but ESEE-6 a bit better). If you add micarta scales AND a kydex sheath to the BK-7 then you might as well just buy an ESEE-6 instead because it will cost less.
If you buy a BK-7 and use it, then buy a kydex sheath and use it some more, then buy the micarta scales - you've spent more than the ESEE-6 would have cost. Then again you've spread the cost out and I don't think that what you have is in any way inferior to the ESEE-6, just a little dearer.
If you don't care about the sheath and like the grivory scales then the BK-7 at under $70 is easily $50 cheaper than the ESEE-6 - that's great value and the BK-7 would be a good buy!
To the OP:
I don't think you'll regret buying the ESEE-6, the BK-7 + kydex sheath would have cost you almost as much and you still wouldn't have the micarta scales. Since you preferred the ESEE anyway and wouldn't have saved much by going with the BK, you made the right choice.