Buying, drinking Darjeeling is like buying, drinking wines. They can be crisp, dry, fruity, flowery, sweet, nutty, vegetal, smooth, ASTRINGENT. The aroma can be heavenly to intense.
They are so variable, a class of tea unto themselves.
As Sal pointed out, they are not all great. I have found that I have to target ones costing around 20 bucks or more per 100 grams.
Another plus is that Darjeeling seems to be ahead of the organic learning curve as many organics are as good as non organics.
Having said all that, and admitting that I love them, I have never craved them in the same way I have say a really good Keemun black ... very strange.
Also, unlike Chinese and japanese teas, the best of the best Darjeelings leave the country. In China, the best may be owned by the government or at least appreciated by the masses first. Japan's best are typically reserved for domestic consumption, and for years only crappola left the country.