It's better to learn one line well than several lines poorly. No matter which line you go with, learn the basics of it first--what you are trying to do and (more importantly) why--and play it as often as you can against stronger players (200-400 points). Study your games first and work on/out the details, then get help from outside sources (coach, computer, friends, forums). When you learn where the transitions are, this will aid in learning other defenses and your chess abilities overall. Remember this, too: No matter how attracted your are to a line, results matter. Early in my career, I tried the Gruenfeld. It just looked like the proper way to attack d4, but I rarely lasted to move 25. I got crushed so many times I had to give it up, and so I adopted the KID, and I found that I have a natural "feel" for the KID--I've been playing it and winning with it for years. Try to learn it as best you can, but don't be afraid to admit it if it comes to "I don't get it."
Scandenavian vs Sicilian Defense, which one to play?
Sort:
Yeah, I play the French vs -2200 and Sicilian 2200+. The French gives weak players headaches and the Sicilian has some similar counter-attacking ideas, but it's mostly an OTB decision as to which to play. It's the same with the KID--some variations are the same as a Benoni, but by a different move order, so it's best to learn both and have two weapons as black.
I am a strong casual/low intermediate player that likes to play both the Scandenavian and Sicilian Defense openings against 1. e4. Just recently, a friend of mine that is a 1500 player said to me that I need to commit to ONLY ONE of those openings in order to become at least a Class C player (OTB) or better. I trust his advice, but I honestly don't know which opening gets more consistent wins at my level.
From my experiences, the Sicilian allows me to develop naturally, but then my king side faces serious harassment from Anti openings like the Grand Prix and the Smith Morra Gambit. The Scandenivian is a lot less theoretical and my king is safer, but it's annoying when my Queen gets chased around the board. I appreciate any help given!