Sorry it's the opposite, the AG is the left piece and Jhanpixel's is on the right. They both stack bubbles nicely, especially with something like Rezblock. The percs are similar, you can tell the mini king on the right is bigger, it's a bit more of a hum (effortless to clear). The AG (12") is definitely the mini-tube and a bit more fizzy of a draw (clearing is effortless but it's so small there isn't much to clear). The Mini King (15") is bigger all around from the mouth-piece to the size of the stemline, the stacking bubbles might be a bit bigger but I can take a hit until my lungs won't go anymore. (sometimes I'll fill it up, exhale and then take my hit so it's not airy) I've just used the AG piece a few times with my Cloud but it's very smooth especially for the size. The mouth-piece is narrow, I thought I wouldn't like it but I don't mind it, it's different.
When I use the Jhan's Mini-king I feel like I'm taking a more traditional bong hit and when I use the AG upline I feel it's more similar to a hydrotube. It's more the volume of the pieces than the percs though; not sure if that helps. I really like them both!
Edit: Now that I think of it the upline reminds me of the Colie Glass recycler. It has a gridded inline, a few less slits but same fizzy draw with the same narrow style mouth-piece and small volume. I kind of wish I had a male nail now, I want to try the upline with wax.