I've got a Zephyr that's slightly older than what you're looking for, it might be a good baseline to draw from.
Tone: bright and powerful, it really sings.
Intonation: well, it doesn't play itself, it's not the easiest alto I've had to play in tune but it's far from the worst. My wife can make it play spot on in all registers, so it's probably at least half the player. Then again, she plays alto almost exclusively where for me it's an as needed deal, so I hardly ever practice with it.
Ergonomics: It's as good as anything from its time, more or less. Feels overall pretty similar to my wife's Balanced Action, except the LH cluster is a little bit less nice to use. I really like my wife's BA. Half the reason I married her (joking!). She borrows the Zephyr if the Selmer goes out of adjustment.
As far as value, price, etc... these are very undervalued saxophones. I have $1200 tied up in mine, and that's probably way more than its worth, especially as mine's been relacquered twice. I typically prefer to leave finish alone, you can't play the finish after all, but if you'd have seen it beforehand... it was a necessary evil. Previous owner had it redone in the '50s (nickelplated the keys) and left it to rot in a moist basement. It's a miracle the engraving is mostly still visible after all that. Bought for less than $100 and then a grand on restoration and a case. Probably worth $500-700 tops. Even original lacquer horns go for less than a grand in fantastic shape, the only Zephyrs with any real value are the "special" models.
Still, people pay a few grand on a Cannonball to have it drop 50% when they walk out the shop door, so I don't feel I did too badly in the end. Saved a piece of history, and it's all the alto I really ever need. Looks pretty sharp, too...