Star Trek is very hit or miss (mostly miss). It's got some great ideas, but the space utopia (built on ethnic cleansing and genetic tinkering though it may be) is kind of a boring and alienating concept. Some of the films are good though. I adore Undiscovered Country. The kilingons in it are glorious.
Star Wars is just fun. Combine western in space, with the timelessness of the Hero's Journey and a few good sammurai influences and you have a modern fairytale. And the universe was fleshed out so interestingly, with lots of fun aliens and planet, and a nice interesting evil empire. Everyone loves a good evil empire with all those nice uniforms, and theme tunes.
I enjoy them both. They're both good for different reasons. They're both sci-fi but that's where the similarities end. I love Star Trek for delving into culture, philosophy, and exploration. It really talks about the big questions and the original Star Trek show was incredibly progressive for its time. Star Wars is more an action packed mythological epic. I love Star Wars because it makes you think anything is possible.