I've never used a dice tower before, and I was wondering if they are worth buying.

I saw one on Amazon that had a cool sci-fi theme, now I need to justify buying it to myself.

It's just one more thing to carry around. Unless you only intend to use it for home games.

I use one when I play at home. But I don't take it with me anywhere.

I didn't buy mine, either - won it at a Gen Con raffle for Axis & Allies events. I do like it though - keeps you from hitting game pieces with rogue dice by mistake.

I worry about the fighters and let someone else worry about the towers.

They're actually fairly easy to build using foamcore and a knife. I don't use one for X-Wing but I built a couple for the Bloodbowl league I ran... With bloodbowl it's not always easy to find a place to roll the dice, and I was able to glue logos for the sponsors on it, so it fit into the game.