I make my own chips and like it but only bought chips a couple of times so have not compared very much. I have easy access to alder, and have gravitated to using that for everything I smoke: salmon, trout, venison, BBQ pork...
Up the BC coast almost to Alaska, Native people told me 40 years ago that how you cut the wood makes a difference in smoked salmon flavor. Of course, they were so used to salmon that they really could tell where most were caught by the taste and texture when smoked or cooked. I wish I could ask them about how big of diameter and how seasoned the wood should be. I prefer stuff dried for at least six months but not old super dry wood, no bark at all.
They told me that alder cut by a saw produced a different flavor than chips cut with a blade such as axe or big knife. I probably could not tell the difference but use a machete and sometimes a block plane to produce wood chips and curls from alder poles, cutting mostly with the wood grain.
A friend made some alder furniture and I saved a bag of cuttings from his planer, and those have worked well also.