As far as I know, Google Sites, per se, are really limited. More so than Wordpress.com in that the number of themes is very limited. I believe just like the Classic Google Sites, it's basically "point and click." It doesn't really matter what language they are created in, since you don't have access to the backend and can't do anything with that code.

If you want to use Python or something to create a website, you need to bump up to Google App Engine.

What would you say are the advantages of Google App Engine vs. other cloud solutions such as Amazon Cloud? I've been trying to find a web developing company that specialize in Google App Engine but most companies I've approached so far tell me that Google App Engine is not the best choice and doesn't have a future. Since I'm not a programmer or web developer myself, it's hard for me to understand how to select the right solution but from what I see, Google is still setting the standards when it comes to things like mobile search, responsive design, etc. so why not use Google App Engine and Google Cloud? Many thanks.