The new Sheridans are not the same as the old ones of 25 years ago, although they are still nice pumper airguns. The merger of Benjamin-Sheridan some years back sealed that deal. I think that was even before Crosman acquired them, but I'm not sure about that.
I kind of like the idea of having more pellet options with the .22 caliber guns, but if you are willing to order in larger quantities (so you don't run out), or have a good supplier nearby, it's not much of a problem.
The guy who has to make sure he orders in quantity is the person way far away from any large cities, and whose major source of sporting goods is Walmart, etc. They tend to carry some choice of pellet in .22 caliber, but not much at all in .20 cal.
Either .20 or .22 cal will have fairly-good knockdown power, so you won't end up with a dog either way IME.