I've just upgraded to a 65" Q8 and the inbuilt front speaker (that looks like a mini soundbar running the full length of the bottom panel) is surprisingly decent. It is arguably bigger than the YAS-108 anyway. I can't find any specs on the frequency range or what the in-built speakers actually are (how many speakers behind the mesh, size of drivers ,etc).
I have a Yamaha YAS-108 which is probably showing its age now. Do you think this would still be worth using? It's a bit unsightly on the wall and it is hard to tell if it is still up to date with the latest dolby/DTS/etc that movies/streaming are using.