I'll say a bit on the condensation thing...

First in hot weather when you are using the bug bivy it is pretty much a complete non issue.

With the regular bivy I still have found it manageable. I use a down sleeping bag with a DWR shell with my bivy. I am careful not to turn and breathe with all my breath going into the bivy, but keep the mesh in front of my face. There is a little condensation, but I have not found it to be a big problem. My down bag have never gotten wet enough to be an issue. What moisture I do get is in the form of a little condensation under the sleeping pad down by my feet (easily wiped up) and a few drops beaded up on top of the shell of the sleeping bag that brush off the DWR shell without soaking in. If it wasn't a DWR shell I still think most of it would brush off and it is little enough that a little airing out and some sun once in a while would handle it.

It helps a lot if you can choose between a regular bivy and a bug bivy depending on the expected temperatures. On really long trips I have often had half of the trip where the other choice (bivy vs bug bivy) would have been better,l but it was never a show stopper. On a long enough tour I could have had the other one mailed to me if it were a big enough deal. Also if it isn't buggy and is warm you really don't need to be in the bivy. I'd rather cowboy camp when it is nice any way.

The only time the bivy ever got really kind of miserable was when it was really hot and buggy. If you expect that kind of conditions take the bug bivy. Worst case you could take both. I never have, but my bug bivy only weighs 5.3 oubces so it wouldn't be out of the question. I'd be more likely to choose thr more suitble one for the first half of a long tour and switch mid trip if needed. I could see using the USPS to swap in Pueblo on the Trans America for example.