In my rifles with 7 mag.,25-06 and .270 The IMR4350 and IMR4831 were slightly less accurate than H4350 and H4831.
I guess having big jugs of both signifies a "real old man"...
Get it when you can, load up when you can.
Powder has a really long shelf life. I have vintage H-110 and H-4831 that are 50-60 yrs. old, still shoot like fresh powder. But ya gotta store'em right.
DF