I have been having a great time banging around with Geoconvert. It is a trial and error process. I have been experimenting with resolution levels and the like. I think one problem many people might be having is trying to always use high resolution. I found that a setting of two or even three on FSEarthTiles makes very good fly over scenery. If you are using the Geoconvert helper tool you can then set it for something like levels 9, 11, and 12 and create great scenery without crashing Geoconvert or using up all of your drive space with the finished product. It also allows you to make large areas, which minimizes the low-res strip issue. I did the entire area between Innsbruck and Vienna in one run, and it came out great.
Of course in an area that large there are areas of the scenery that were taken at different times of year so they don't color match, but that is another issue.
My advice to anyone who is sitting on the fence is to go ahead and try it. It looks much harder than it really is, especially with the video tutorial that we now have.