Experience with Sekisui House

I am currently looking at different house makers for building a house. I came across these ready to sell houses by Sekisui house which I liked a lot.
I like the design appeal and they fit in my budget, and the best thing is they are ready to sell meaning I don’t have to go through the hustle of looking for a suitable land, paying hefty amount to the land owners, design meetings, monitoring the building the house etc. They are ready to move in within couple of months once the loan is cleared.
I wanted to know if there any downsides of these readymade houses? Does anyone have experience of buying these houses? What do you think? Merit or demerits?
Will appreciate your kind opinions.

Thanks