Shabaz posted a blog on this subject but RPi based - I suggest you look at that.
Each one has its own pros and cons....If you are looking for some Relays and Gpio modules whether it is ethernet or wifi or usb , you can find it here.
Wifi is cheap and has usually a longer rang then Bluetooth, also you can setup a page hosted by the WIFI module like esp8266. And connect to it with all devices connected to your network. Also its possible to setup a remote connection and connect to it anywhere in the world as long as you have internet, and if you have a Bluetooth module you have to make an app to control everything. While a wifi module can host a HTTP page with websocket.
If you are intrastate in using a wifi module I would recommend you check out CNLohr on youtube https://www.youtube.com/watch?v=8ISbmQTbjDI
I'm thinking about making some home automation. I just stared planning stuff in my head, but came over a question I probalbly need some help with. I was think about making the system over Ethernet, but the more i thought about i started to think it would be smarter making it WiFi. Maybe even blue tooth, but mostly WiFi.
What is the pros n cons about making it WiFi?