As Albatros already said, Basel is one of the few spots in Switzerland where they don't really care about hockey. Football is dominating there. Their MySportsLeague-Team (3 tier) draws some fans but overall it's not an exciting experience. Overall I would also recommend watching games in Zurich or Bern (both within one hour by train).
For your question about the league itself I have to say that right now there's a parity we haven't seen in a long time. Pretty much everyone can beat everyone. But top teams this year to follow are Zurich, Zug and Biel in my opinion. The most intense rivalry is definitely between Ambri-Piotta and Lugano, the two teams from the italian speaking part of Switzerland, it's always worth looking at the game. For a real good fan experience you should definitely go to Ambri as long as they still play in their old barn. It's really unique and the fans are crazy. If you need to know anything else about Swiss hockey don't hesitate to contact me.