The CM7777HD is a good preamp; I have two of them that I use as test amps for setups. But, I really don't like the housing because it doesn't seem suitable for outdoor use. Their other preamps have the connectors on the bottom which provides better weather protection.
Their previous 7777 with the single antenna input doesn't have a good reliability record:
Their new 7777V3 looks promising, but it is as yet unproven. I suspect it will be more reliable.
https://www.channelmaster.com/TV_Ant.../cm-7777v3.htm