They are going to be faster and better than powerline, since they use your existing coaxial cable to create a network. Powerline, in my opinion, is less reliable than MOCA. 2 adapters will cost around $130 to $160 and will give LAN speeds of up to 1 gbps. Plug in one adapter where your modem is, and another adapter in the basement. They're pretty easy to setup, but you might need to get moca filters in addition to the adapters. The filter can be placed at the house's coaxial point of entry to prevent your network information from going back into Comcast's coaxial network.

Another option is to get wireless mesh like Eero or Orbi, but wireless latency might be a problem if using VOIP from home.