True enough. You can find individual horns from any brand that will have that "magic" to them. And you can find "duds" in even the best lines. But most "reputations" of certain brands will hold up over the long haul. Those reputations are based in reality.
Also, it's amazing what "tweaking" by a top-shelf repairman (and there's but a handfull of those in the world) can do to even the most mundane horn. I've seen one of them (cat named Ken Beesom) take old pawn-shop horns and make them into true instruments. That guy's a freakin' artist. He's got original facory specs, and his own machine shop to tool parts. He can take a total piece of shit horn and turn it into something special. But he's one of the few, and he works neither fastly nor cheaply.
Danielle, you gotta realize that when you're talking top-quality instruments & top-shelf instrument maintanence/repair, it's not gonna come cheap (unless you luck into a freaky kind of deal, and that certainly does happen. Just can't count on it.). But if you're serious about this being your life's work, it's time to start thinking of that as a "fact of life" and getting used to the idea. It might not be possible to start at the top when it comes to this stuff, but you should definitely aim for that level of equipment/performance. Start thinking about themost you can afford right now, add what you can get if you make some sacrifices, and go with that as your final answer. Repeat as necessary.
Again, Chuck's right, it's not just about the brand, it's about haveing your instrument - any instrument - in the best condition it can possibly be in. When you get "well-seasoned", you learn how to work around shit when it gets funky. But it's a helluva lot easier when you don't have to, and at your stage of developemant, you want to experience the full potential of the possibilities before you fall into the rut of having your first line of attack being "compensation". That breeds bad habits, which, like weight, are far easier to obtain than to lose.