If I recall correctly, the Drake replaced the Canvasback and has the new design action. I can't comment on whether it is an improvement or not.
The Canvasback and Redhead have the earlier design (103) action, and I believe the Upland Ultralight may share that action as well, but in a light weight alloy receiver. Right off I would disqualify the Upland Ultralight for clay shooting just because it is so light.
The Canvasback and Redhead have been pretty reliable guns. I have a 12 gauge Canvasback that I bought strictly for sporting clays and have found it to be a reliable gun. One of our regulars who has been absent lately has a Canvasback with over 31,000 documented rounds through it without a hiccup. I thought his thread was a sticky topic on page 1 of this forum.
Anyway, sounds to me like you are a perfect candidate for a Canvasback.
Edit: Here's a link to cdb1097's thread on reliability and his Canvasback:http://www.shotgunworld.com/bbs/viewtopic.php?f=137&t=189338