I think both bug shots look great, good depth of field and good focus. I looked at them in PS LE and the seem a little bit too artifacty. The wasp is only 49Kbytes, which might mean you're going a bit heavy on the jpeg compression. I use medium 5 in PS LE most of the time. I dunno Royal, just grasping at straws.
It could also mean that you are reducing the size of the image too much, or picking a size that is not a good ratio. I start with an image 1024 x 768 and first try 512 x 384 or 768 x 576 if that's too small, to see how it looks. I also wait until I have the size I want before tweaking the levels and unsharp mask. I never make a jpeg and then make corrections, because you must save it as a jpeg again. A jpeg of a jpeg is not good. But you probably know all this stuff, and I'm way off base.
The Nikon 4500 can macro focus to within .8 inches of the lens, which is one of the main reasons I bought it. On the other hand, it does a poor job with night shots, and the Sony's are much better at that.
The Carl Zeis lenses are excellent, but I don't know anything about your cameras. Sorry I can't be of more help. Jane and I have been on a little trip, so I'm just catching up on all the posts.
fod