For me, I think Hilton status > Accor status.
Sofitels and maybe some Pullmans are the only hotels that are remotely close to being decent in the Accor chain and a lot of these properties are really dated. Not to mention that they don't do free breakfast even for Platinums (and the Aussie Sofitels didn't allow lounge access either until very recently).
Compare that to Hilton where even Golds get guaranteed breakfast and almost guaranteed access to club lounges, not to mention the usually higher calibre quality of Hilton/Conrads properties compared to Sofitels (very evident in North East Asia especially, Hong Kong or Seoul is an example), I think Hilton is a more valuable benefit overall.
And between Hilton Diamond and Gold, I do NOT think there's much difference at all. This is one of those tiers where the difference is so minimal that I wonder why they have DMs in the first place. In fact, I'd say Hilton Gold is just as competitive as some of the other top tier statues, considering you get breakfast + lounge access + room upgrades (this is usually only offered to other top tiers).
The only difference between Hilton Gold to Hilton DM is the possible upgrade to suites (rare but it does happen) along with guaranteed access to club for DM. It's just that I've never heard any Golds getting denied club access ever.