Coincidentally I had the black bean version of this a few days ago. Delicious, but less spicy than expected. :-)
I ended up trying something like 20 different brands looking for an alternative, and my favourites from least to most spicy were: Chuan Lao Hui, Lee Kum Kee, and Wa!, which I actually found even better.
I tried Lao Gan Ma again now that they're back to chilies from the original province, but it still doesn't taste quite the same, I wonder if the sourcing changes caused them to lose their specific cultivar?