Yes, I have done various tests with chicken, pork, etc. to see what I like and if I, and/or my family & friends can tell any difference, not only in flavor, but also how the pellets perform in our two pellet grills.
As far as flavor difference: cold-smoking is where I can tell the biggest difference in 100% flavorwood versus and oak/flavorwood blend. The 100% flavorwood gives me a true flavor profile for that wood type.
The strongest flavors that give the deepest smoke profile when cold-smoking are Apple, then Hickory (mesquite is way too strong for use in cold smoking, in my opinion). Apple gives a very deep penetrating smoke and aroma with subtle hints of sweetness that reminds me of a campfire. Hickory gives you a very distinct bacony, salty smell and flavor with warm tones. Apple and hickory together are a perfect pairing for pork shoulders!
Color: Different wood smokes will give noticeably different colors on meat. Apple gives a very distinctive dark chestnut color. Cherry gives a reddish mahogany color, and hickory gives a color something in between the two.
As far as performance: There is no doubt in my mind whatsoever that an oak-blended pellet absolutely performs better; good BTU's (for more stable temperatures), and considerably less ash than 100% flavorwoods such as 100% hickory, or 100% apple.
Now that does not necessarily mean they are blended already in the bag. Since I like to cold-smoke certain things I tend to get 100% hickory, and 100% apple to use for cold smoking, then mix them 50/50 with oak for use in the hopper.
So basically... I run oak/flavorwood blends in the hopper and save the 100% flavorwood pellets for cold-smoking using an "A-Maze-N Pellet Tube" or "Smokin Wedgie" (a similar device).
I also really like Lumber Jack's Competition blend (formerly called their MHC blend), which is a 100% flavorwood blend of Maple/Hickory/Cherry.
For grilling on the MAK (FlameZone in Grill Mode): I have not found anything that performs better than Lumber Jacks's Charblend Hickory (hickory/charcoal mix). They are Very high BTU's and relatively low ash. I have not tried the BBQer's Delight Jack Daniels pellets, which also contain charcoal, but I imagine they too would give great results for grilling mode.
One more note: As far as telling the difference between flavors, I still hold that a lot of it has to do with a person's sense of smell, because a LOT of the subtle differences in smoke profiles are in the aroma which then affect taste.
Ok here is how I did it. Tent yours is fabulous and Im not discounting it...very good.
It's a pain to do but I did it. I cook boneless skinless chicken breasts. Let them cool and then refrigerate. I find that the next day you can really identify the flavors more easily with the technique above and there is not interference with seasonings
As Tenthunter noted certain types makes different colors on the meat. We choose cherry the most as we like the color of the finish product. We also like the oak/pecan blends. Honestly pellet flavor is our least concern. I will second that apple is good for cold smoking. It makes great smoked salt.
You can get LJ online as well as in-store. Also, check BBQ Pellets Online. You may luck out and find a Group Buy near you. I just participated in a Group Buy in the Sacramento area. Worked out great and I've got my pellets for at least the next year.