Please bare in mind that this is just the
of a
. . .
The Black Leaf is what is usually called (at least in the U.S.) a bubbler, this 300mm/~12" height is typically about the max but a good size for the Q. The glass thickness, mouthpiece diameter, can diameter, inline length are all fairly standard. My inline is the same size & number of slits; mine are gridded, can't tell if these are (and btw even so mine is still a bit chuggy). The page doesn't provide the height of the tree chamber, looks from the pic to be ~100mm/4", a good size can given that this is a two-chamber piece. The 18/19mm GonG joint IMO is important. I've only heard of Black Leaf so can't personally speak to quality of workmanship or glass; this is in particularly important with a tree-perc as they need to be well made to hold up under use. The other question I'd have is with drag and the action - you're pulling thru 2 chambers and 42 slits - certainly a helluva lot of bubbles, but can't guess what actual perf would feel like.
Re the Blaze bong, an entirely different kind of piece and, personally speaking, I don't see this with a Q (well, not mine anyway). The dimensions and thickness are, again, fairly typical. I can't make out the down-stem; the web page says there is a 18/19mm joint but how is it inside and is it diffused? Seems like you'll be pulling thru a lot of water and then up through a perc which may look "bad-ass" but doesn't appear to provide much diffusion. I have no idea what the feel of the pull would be. And the magnet IMHO is an unwelcome addition to glass that is delicate enough by itself.
Of the two, IMO the Black Leaf is the better choice.