Any of the big four " yamaha, selmer, yani, and keilwerth pro models are excellent horns and have an established resale value and quality build. That said there are some very good horns being made elsewhere but none have the long track history that the big four have.
I personally have owned selmer, kielwerth, yamaha, and now steve goodson horns. I have taken a chance with a newer brand with the goodson and saved a lot of money and really like my horn. I purchased it cheap enough that I don't have to worry about resale value.
A lot of folks are very happy with their P. Mauriats and Cannonballs and a lot of folks are happy with similar asian horns priced much less.
The good news is their are so many good choices out there at every price point. You really can't go wrong with any of the above. The difference a horn makes is very small compared to the difference practice makes. And your tone can be influenced more by your mouthpiece and reed selection than your horn.