I've been reloading for shotguns for a little less than a decade. Gave up reloading for metallics after lots of loads through the old RCBS single stage. I started with Clays partly because the used setup I bought came with a can of it, then stayed pretty much with it because it's inexpensive, consistent, easily available as Jim mentioned and I can load up stuff from 3/4 oz to 1 1/8 oz using Hodgdon's own data and 1100 to 1300 FPS.
My pet load at the moment is......
STS hull.
WAA12SL wad or the Claybuster clone.
Win 209.
17.3 gr Clays.
30 lbs wad pressure.
7/8 oz of hard shot. This time of year it's likely 7.5, summers 8 or 8.5.
Load's right from the Database on the maker's site.
Stick to published data,and NEVER, EVER substitute anything else.
HTH...