I can not recommend this game enough.
I loooove the board game version, and I am so happy that there is an online one that I can log in and play for hours.
It's fun and almost feels like the real one ( I say almost cause nothing beats the face of a friend when you block them ).
If you ever played and enjoyed the board game, you'll love this one too. And you can almost always find someone online to play with, wich is great. But even if you don't you can always practice with the offline version against the cpu.
If you are new to the world of ticket to ride, give it a go and you will not regred it. It is really easy to learn and you can have fun for hours. Suddenly you'll find yourself trying to persuade some of your friends to tag along. If you still not sure, go rent from your local library and try it, then you'll definatelly get it.
What are you waiting for? Do it...