Well, for target shooting, the larger scope would be easier to hit.
Sorry. Couldn't resist.
Seriously, you will probably get few responses on this forum about either of the scopes you mentioned. Swarovski, Leica, Nikon, and possibly Pentax seem to be the magic words.
I am interested in the Celestron 80mm 20-60x scope. It looks pretty good to me. Astronomics.com carries it for a good price. Adorama.com carries it for cheaper but I would rather deal with Astronomics. I've done business with them before and I have never had a problem. Actually, I've never had a problem with Adorama, either. You just have to deal with abrupt and sometimes surly New Yawkers. Astronomics has free shipping on their scopes and binocs -- so the prices might even out.
Some people talk about the ED version of the Celestron 80mm but it's over $300 more and I just don't think that price is justified for putting an ED element into an otherwise identical scope. Astronomers are skeptical that ED does much to elminate optical deficiencies at low powers, anyway. But you will hear differently from others on this forum -- many who have sunk big bucks into scopes and binocs with ED lenses.
I am curious why you are dissatisfied with the C90 -- that is also a scope that I am looking at. For birdwatching, the C90 has some limitations as far as slow focusing and the use of powers lower than about 30x -- but for targetshooting, I can't imagine those are real issues. The target is stationary, and higher powers can only be better, right? Just based on my experience with my daughter's 4-H shooting sports group.
A quick look at the Konuspot 80 leads me to believe that it is identical to the Celestron 80. Celestron products are made in China and Japan -- I would imagine that Konus is too.