They make high quality pieces and some of their fans are particularly stellar in the static pressure dept. for use on radiators in water-cooling setups! (The F12's are wicked fans) The color scheme is what is, you either like it or hate it, (There are black noctuas also, not just cream and brown) I've used Noctuas for a long time, and they are robust fans, quiet, and perform extremely well in the setups I've built.
All this being said, are they the best? Thats up for debate, user preference, and application are all factors.
You wont go wrong with their products, but yes, there are other alternatives, as with anything in the computer world!