H335 is a sweetheart with the powder measure... but I really like the way H4198 gives me similar (better?) performance than H335 with less pressure and a nearly 20% lighter charge weight.
No, it doesn't meter near as well as H335, but it sure does perform. The next time you can't find H335, see if they have a can of H4198 and you too might find that you have two go-to powders in .223!
(of course, I just assumed you were talking .223, but you might have been talking any of a bevy of other calibers... still, if H335 is good in it, H4198 may also be!)