I agree with Strix if going with 2x16. Seen no feedback on Asrock, Gigabyte has issues with DR past 3600-3800, MSI is ok to around 4000.Thanks, I'll take a look.
Asus Tuf will get very close to Strix as a couple people on overclockers.net had both and clocked about the same on mem and CPU OCs.
None do very well with 4x8 so be aware. Probably 3600-3800 will be limit with 4x8 from what I have seen.