My instrument of choice for over 38 years, this is no nickel-plated horn ! The very large bore Conn 28D horn in brass was a great horn, my teacher, a 4th Horn specialist had one, but it had just too dark a sound for the horn community as a whole, Not so easy to find one nowadays, therefore.
To brighten up the sound, Conn tried making the whole instrument out of solid nickel silver. But lacquered.
This was the Model 8D, a bit dearer, but "just right" for very many players, and for a long time it was said to be the most widely professionally-used model of french horn in the world.
To me, the 8D has a much more definite "feel" about it than the 10D, which just seems to be trying to be like other horns - American, British or Japanese.
The musicality is all there, but tuning's a bit harder work to begin with than with narrower bore instruments, so expect a brief period of adjustment when you first come to actually play it with other people. But it's always you, not the horn, that is in control, which I personally haven't felt to be the case when I've tried the standard continental offering.
The 8D has a crisp positive B-flat side that can play both low and right up to the top end concert F to B-flat range more easily than many other and maybe shorter horns. Then there is the F side that is just asking to be played a lot - not just used for "playing low G's and F-sharps" and for going through the Dukas Villanelle and (enjoying) the Farkas warm-ups.
The case is quite strong, but the case handle wasn't, and needed a steel replacement after several years. Experienced players rightly ignore "supplied" mouthpieces, but my 8D came with a very respectable and unusually durably gold-plated Conn horn mouthpiece.
But I might still try a 28D one day!