There are some folks that weigh in and say that any woods burned to lump, lack much of the original pre-burnt flavors. I use the Maple lump and tend to agree, to a point. After a long cook, say like a pork butt, there is some subtlety to the flavor, almost sweet.
That being said in regard to flavor, the Maple lump is the best lump that I have ever used. It burns consistent, not too hot, and suits well for WSM work or doing steaks on the kettle.
My .02 is buy as much as the truck will hold, or the wallet will support. I sincerely doubt you will be disappointed.
I have come back to add a bit, here. I am only aware of one brand, that is available for the Maple chunk charwood. The brand I am using is called Nature's Own. It comes in bags packed in 17 1/2lb. lots.
Is this the brand that you have available to you?
Jim