Certainly! The base game is already a good amount of fun, there are a few extra modes to be found, but the main focus is on battle. The workshop characters, however, add a lot of chaos into the mix. They can range from very balanced fleshed out characters to 100% accurate Fox who zips around the battlefield. The game also used to have paid DLC characters, but those are now included with your purchase.
The net code is solid, and if you play the base roster, there's rollback netcode, which allows for much smoother play on bad connections. Online against random people is mostly dead though, because the sequel's release is underway. I personally don't really like it, but it looks and plays a lot more like Smash Bros.
There are some good arguments for not using the escape key, but there's also another benefit:
You don't need to reach over to hit it. Normally, your hand rests near the shift key, so using it is a much more innocuous action than lifting up your hand to reach over to the upper left corner.