I've used 700-X for several years beginning a couple of years ago when 231 was unavailable. I use it for 380, 9mm, 38 SPL, 357 Mag, and 45 acp. It is too fast to be a true magnum powder, however.
It burns fast and clean. Being a larger flake powder, however, as others have said, it doesn't meter well. I use a Uniflow for dispensing powder. I bought it 40 years ago. It came with both a large and small cylinder back then. All these years, I've used the large cylinder not even thinking about the small cylinder.
Then, reading on the forums, I saw where folks were getting better throws of flake powder like 700-X and Unique using the small cylinder in the Uniflow. So, this weekend, I cut open a 40 year old plastic bag containing the small cylinder and installed it.
I reloaded about 150 45 acps using the small cylinder with 700-X powder this weekend. The small cylinder does throw 700-X more consistently than the large cylinder, so I'll keep it in the Uniflow. The charges were not all spot in but the degree of variance was less. The variance was such that I felt confident enough not to weigh each charge. Checked every 3rd to 5th charge or so. I load well under max, so there is some safety "freeboard" there to account for some slight overage in charges.
I've never used a powder baffle, but others say that helps consistency, too.
I've never used 700-X for shotgun.
$77 for an 8 pound keg must be a mistake. 4 pound jugs go for about $79 or so, at least that I've seen on-line and around here. Thus, if you can load up on the 8 pound kegs for that price of $77, you're in the chips, my friend, and I wouldn't look back.