Looks like it might be best for billets, cause of the twist, though you won't really know until you start to split it.
I am surprised it hasn't started to check. I have seen weathered logs like that and they had lots of checks(still bows in there though).
A good find, but I'm glad its you doing the splitting and not me as my shoulder has barely recovered from the last batch I did a couple of months ago(getting old sucks).