Okay, now for a controversial entry.
Because I'm cheap and poor (well, actually I'm cheap because I'm poor), I went for a low tech, low priced option in the form of a triangular, meshlike product. It's similar to Gutter Stuff, but I don't think that was the brand name when I bought it. I can't remember what exactly it cost me, but I believe it was only a couple hundred dollars. I also installed it myself in about an hour and half.
BUT, according to this guy, Gutter Stuff is the biggest scam of our lifetime and is absolute crap that should never be sold, let alone used. The thing is, my house has five 70-80 foot Douglas Fir and Cedar trees overhanging it (which destroys the shingles, BTW), and in the 10 years I've had these guards in, I have had no problems, no breakdowns, almost no maintenance, and no leaks or blockages. My father has had them in about the same amount of time because he did his house after I did mine. He's also has had no problems. Ymmv.