I enjoy using two long focal length refractors. They are both home made using lenses from D&G. One is 6" f15 and the other is 5" f15. They are very sharp and a lot of fun to use though they both show some chromatic aberration. They are very high contrast and perform very well for their aperture. There is a nostalgic charm to these old style refractors that I enjoy. They are simple and need almost no maintenance just reasonable care.
I would expect equivalent aperture f8 fluorite doublets to perform better with reduced chromatic aberration and much easier handling with the reduced length. They would also be much more expensive.
Sadly D&G have not been making lenses or telescopes for amateurs for a couple of years now despite their website still showing open for business. As far as I know they have been busy with other contract work. I think they will still fit in repair and restoration of historical lenses where possible.
Here is my review of the 6" from many years ago.
http://www.iceinspace.com.au/41-340-0-0-1-0.html