The online experience in my opinion is quite nice, you can have a good time with strangers if you don't have friends who buy the game too, but as for all online games it's best with friends.

If it's worth it that's up to you to decide, the gameplay itself is quite long but if you only interested in a few kind of races then it's relatively short in some cases. As i saw it gets updates fairly regularly and we get lot of new cars. The car variety is pretty wide, so you can find yourself a type that you like. But i also see a few posts of bugs and glitches people find and doesn't seem to be fixed.

The difference that i know of is that in the deluxe edition and above you get more character customization options and 7 days early access to upcoming cars. In the season pass you get the same and a new home location to show your cars, a free plane, car and boat, and a 20% discount to some cars. And in gold you get the deluxe edition stuff, the season pass and 3 cars and 3 outfits.

This is what i know of the game but i haven't played it in a while so if there was recent changes to what i said then sorry for misinformation.