I have a Mallory Unilite in my '56. Replaced a W&H Du-Point (straight from the Edelbrock catalog, in the car since late '56).I hate dual points, but to each their own.
Been very happy, and very easy to set up. Pretty limited on advance curve (set up with factory '57 Bird curve), with no vac advance and some folks have little good to say about them, but I'm happy and it performs well and runs strong to 6k rpm in a mild 312. Concours parts sells a tach cable for it, that fits perfectly.
I bought mine on amazon.com for $365 or so. Very pleased, though it's 1 1/2" or so taller than the old dual point. No clearance issues though.