My 2 cents.
I am a complete tea newbie. I used not to drink tea, which I associated to overly bitter stuff sold in small bags. But last May I tasted two teas I found so good, that I have started a journey in tea. One of those teas was a Darjeeling, the other one was a Jin Jun Mei (JJM).
The reason I feel I can chime in even though I am a newbie, is that I used the JJM I found so good, as a starting point to test teas. I first tried to find teas similar to it, then branched out everytime I found another good tea (and I have found some that I like better
). So far I have tested more than 100 teas, including several ones called JJM, and I have kept records of all tasting sessions.
After this introduction, here is my opinion.
Yin Jun Mei: it is indeed less expensive than JJM. It is a very good tea but completely different from its semi-namesake.
I believe it is made from the same cultivar, but it is lightly smoked. So if you like lightly smoked lapsang souchong, you will like Yin Jun Mei.
JJM: I am pretty sure the one that got me hooked on tea was NOT authentic JJM. It was pricey as teas go, but certainly not at the price level I am told authentic JJM goes for. I have not been able to find a so-called JJM as good as the first one. "Never as good as the first one", LOL. So for the time being, I am sticking to my source for this one and I have stopped testing other JJM.
Similar teas: JJM is a pure bud tea. You may like to try other pure bud teas. I did not find a pure bud tea tasting exactly like JJM, but many have a "something", a "Je-ne-sais-quoi", a commonality with JJM.
This is actually how I found a red tea that I prefer to JJM. It is Chuan Hong Jin Ya. It tastes different, more floral, and I just love it. Even if, my favorite teas are now oolongs. But thank you JJM, you got me started on tea.