Pecan has been my favorite chunk wood to use with my charcoal smoker, & I have a couple bags of LJ Pecan blend pellets, having recently finished one in the 590. Overall I prefer pecan with just about any food because it gives a nice mellow smoke flavor with no harshness that can come with some other woods. Decent results with the pellets, though fairly mild flavor impact. I've only used the LJ Pecan Blend (which includes oak) so can't compare to 100% Pecan pellets, though wouldn't mind trying if those are even available.
We like Pecan on the smoked almonds. Also did something crazy and used Pecan on candied pecans.
Turned out great.
I have a bag of Alder I haven't used yet. Another not-to-common flavor. Grabbed it because the shelf tag read DISCONTINUED.
Supposed to be good with seafood.