Technically, AsusWRT is forked from Tomato. There is, however, openwrt based entware/optware package managers for MIPS and ARM based routers, respectively, when utilizing AsusWRT-Merlin. Asus also runs some additional packages via their own hosted optware repos, but these are generally outdated, with exception to certain core extras.
Personally, I think the AiCloud features are nice in theory, but I also prefer the more standard options. AiCloud has companion android/ios apps for the less technically saavy.