@Muzza145 

I would recommend X50 or X55. They are similar to X60, but their feature set is better aligned with M5. Also, X50 and X55 have 3 Ethernet ports which could be more convenient if you plan to wire them. X60 has 2 Ethernet ports.

  @Alexandre. Hi! And tanks for your reply! I'd follow your advice, you recommend buy 2 units (x50/x55) or 3 units. 
and what about getting 3 x20 units (for the M5), should I get a better average coverage?

Best!

  @Muzza145 

How many floors does your new house have, including basement if it has basement and you want good WiFi coverage in it. 

  @Alexandre. No basement, one floor, 3 bedrooms, but I'd like to keep my options open if in the future we move to a new place with 2 floor (we don't like houses with basement btw). 
We use the internet for tv, home office, and a few cameras...we are not a heavy internet consumer, but we do like to have a good average coverage 

best @alexandre. And thanks for your help!

  @Muzza145 

For two floors house you can start with two new Deco and use M5s to expand coverage on each floor. Each floor will have one new Deco and as many old M5s as you need to provide WiFi coverage you want.

Can you wire all Deco at your house, and at your future house? If you can't wire all of them, old M5s and new Decos, I recommend going with X50 or X55 for new Deco. 

In case you are confident you can always wire all Deco you have or will have, you may choose X20s as new Deco, too. 

  @Alexandre. Thanks mate!