KitGuru tried the MSI X299 SLI Plus Motherboard
A quote from the article:
Intel's X299 platform is an appealing choice to consumers requiring high core count CPUs and plentiful system memory. Yet an X299 system build can get seriously expensive with the motherboard comprising a large share of that expense. MSI's X299 SLI Plus motherboard proves that getting onto X299 needn't be as expensive as you might think.MSI X299 SLI Plus Motherboard Review @ KitGuru