Different strokes, and where you're from, affect smoke flavor preference. Not a lot of hickory up north, so Brian's preference is certainly alright! While I love many of the fruit woods (especially cherry), it there were only "one" wood we could use for smoking, my hope is that it would be hickory! I grew up smelling hickory at almost every BBQ joint I've been to, and to me, it smells like BBQ!
To your question about different tastes of hickory - absolutely! All hickory is not created equal, and where the wood comes from is a factor. Good-quality hickory is great; over-dry, or too much bark hickory is bad. I have used the dowels from SI (which are a really good-tasting hickory, all heartwood), and hickory from Fruitawood and Maine Grilling Woods, which have also been very good. A lot of the bagged "big box" store woods (to include Weber) are usually too dry - which is probably where some of your bitterness is coming from. You may actually be getting a little combustion, which definitely changes the profile of the smoke.
Good, quality wood, and not too much of it, always yields the best results!
