How would you describe the taste of a rough lemon?

I have a tree that I believe is rough lemon based on the fruit that it's producing. The fruit's characteristics match that described in The Citrus Industry. As well, pictures on the web back that up. The rind is quite fragrant and the flesh is juicy. To me the fruit didn't really taste like a lemon but more like a sour mandarin. What's interesting is even though the initial taste is sour the aftertaste is sweet. Would you agree?

I would agree, but my emphasis would be on sour. They dont quite hit lemon sour, but are pretty close. Rangpur lime is pretty much sour mandarin flavor.
These are similar plants, both lemandarins, maybe also check if its Rangpur.
Rough Lemon can be slightly variable from seed, but a rough skin, round lemon sour fruit, with a lump/nipple underneath is what it looks like. Seeds are fairly small for the size of the fruit. Leaves are more found tipped/Citron like than most lemons.

I'm guessing it is rough lemon and not rangpur. The tree grew from a cutting I took from a supposedly ungrafted Meyer lemon but there must have been a rough lemon rootstock on that tree even though it didn't look like it was grafted. Did you also experience the sweet aftertaste?