When I am interviewing a client for home automation I always ask the following question:
1 What do you want it do.
a. Turn lights on and off, Lights turning on/off automatically at set times
b. Heating control
c. Control TV and other media usually via IR
d. Wireless systems or wired or a mixture
e. Do you want to control the system when away from the house via an app
f. Future expansion
Once you have got most of these things answered that then gives you an idea of what system to go for.
Future expansion question can be hard to answer, but normally I suggest it things you may want to control in the future, like electric car charging, automatically topping up the swimming pool or pond, adding cctv cameras into the mix.
You will find certain things easier on some systems than others so you need to prioritise which functions are important to you.
Lastly remember not all wireless systems are the same, mesh based systems are much better. Mesh systems usually work by working out if a module can comunicated directly or needs to talk to another module first. Some systems require you to manualy set up the mesh, which can be a pain if you move a module,and forget to change the mesh network and then the system stops working.
I normally suggest Loxone to my clients, so youmight want to look at this, its not cheap but its not hugely expensive either compared to some. Especially when you consider all config software and apps are free. Also it works out the mesh network automatically, so if you move a module it will adjust accordingly ( I have tested this and it takes about 5 minutes)