The biggest thing I didn't appreciate about watching CS live before I did it is the atmosphere in the arena. I went to the London major with some friends, 2 of which hadn't watched any pro CS before and we had a great time. The atmosphere, especially if one of the home teams or players is playing, is great.

It depends on the event. I had to come a few hours early to IEM Katowice to get good seats and stayed in the arena the whole day but it was worth it. However, when I went to Berlin I only watched one of the 2 bo3 series played each day and spent the rest of the time looking around the city. Either way I had a great time.

Imo if you can follow the game and enjoy even watching even 1 map at a time at home, you'll have a great time at pretty much any event and the time will pass quicker than you think. All the events I've been to so far, big and small have been great and all offered a unique experience.

My advice is, when there's next a CS event near you, don't miss it. You won't regret it trust me.