I know the tech who does work for them, and he does great work.
Reputable dealers are always recommended, but if you're bargain hunting, I always recommend checking local marketplace and Craigslist ads first, specifically the ads allowing local pickup so that you can inspect the horn before purchase. This only works if you have at least one local shop that does great work, and has reasonable overhaul rates. Factor in the price of a full overhaul into the purchase as the worst case scenario. If it's still cheaper than the market average, you found a deal. Bonus tip: search for common saxophone misspellings. You'll often find someone who is just looking to make some more storage space in their closet, and they really don't care what that horn is actually worth. Ethically, you should tell them. Realistically, they usually already know. They don't care. Just get rid of it.