In my opinion H4350 is better than IMR4350 -- it tends to be a bit more accurate and to give higher velocities with max loads. But the Hodgdon powder is a bit slower, so loads you developed with IMR4350 will almost certainly not be the same with the Hodgdon powder -- you will probably need a bit more H4350 to get the same velocities that you got with IMR4350.

I would buy a pound & try it 1st. It is a bit slower than IMR4350, so it's not completely interchangable. I like it in several loadings, it seems a bit more accurate.

H4350's shorter grains meter much better than either IMR or Accurate, so I use it as much as possible, in the calibers you mention and some others (it's the cat's whiskers in the 7-08 with 145/150's, for instance). I've found the three 4350's to be pretty much interchangeable, as long as you use the standard "reduce 5% and work from there", premise, same as you'd do when using a new lot of the same powder you had been using.

H4350 is supposed to be one of the "Extreme" powders, thus less temp sensitive, but, I haven't been able to personally verify that (when it's really cold out there, I'm inside by the fire ). In some, admittedly not to scientific standards, testing I did with H4350 vs IMR 4350 in a 7x57 with 150 Power Points, on two different days (55 degrees F one day, 20 degrees the other), the load with H4350 stayed within 15-20 FPS of the original reading, while the IMR load was lower by nearly 100 FPS on the cold day. Of course, now that Hodgdon bought IMR, maybe the IMR stuff will be "extreme'ized" and all that won't matter any more.

MidSouth, Natchez, and Graf's often have the 8#'ers at pretty decent prices, so, if you have a means to store it properly (cool, dry, dark) I'd get it. One nice thing about an 8# container, once you DO get a load worked up, it'll be a long time before you run out, so, you don't have to worry about re-working the loads as often as you do every time you open a 1# can from a new lot. Something to think about.