What server side language should I use? PHP or node.js? Or something else??

Answer 1

Both have there pros and cons.

PHP
Pros:
• Easy to deploy; Just install PHP, do some configuring (you should definitely configure PHP but it's usually not necessary) and drop your PHP files in the webroot.
• Used everywhere.
•Easy to learn.

Cons:
• Weak language; Because PHP grew organically it is a very odd language and has many querks.
• Because of how easy it is to learn you'll find some really bad code out there.

Node.js
Pros:
• It's JavaScript with some goodies so if you know JavaScript it'll be a breeze to learn.
• It's very fast.
• Asynchronous meaning it can handle concurrent requests easily.
• Can interact with the user directly unlike PHP.
• NPM.

Cons:
• Not many mature frameworks.
• Not as widely used as PHP.
• Only runs on one CPU so doesn't scale as well.