One important reason is visual interest, which is important to a lot of smokers. All those glass rods do look good while working in harmony. Additionally, some people like them for the nostalgic value.
There was a long period of time when tree percs made up more the majority of all percolators, so some people just like them because their first bongs had tree percolators. Regardless of artistic or nostalgic value, tree percs do in fact still do their job, and do it without creating much drag, so while a tree perc isn’t inherently bad, it’s just not our favorite. Showerhead percolators go by many other names, such as UFO, tire, and others. They were one of the first percolators to come after tree percs and have a very similar design. They use a tube that comes up through the middle from the chamber below, which is covered by a larger tube reaching down to the perc where air and smoke exits into the water as bubbles. This design can be clearly seen in the image on the left. There are many different designs, ranging from 4 slits to multiple tiers of 50-slit showerheads, as well as more artsy designs with bulging spheres in the middle to resemble flying saucer type UFOs, hence the name. They suffer similar downsides to tree percs, however since the slits are not stacked vertically, their water flow tends to be more evenly distributed.
Furthermore, since they have less individual parts, they’re less prone to breaking. Showerhead percs may not be the best available, but they make an excellent improvement to downstems. It’s typical for stemless pieces to start off with a small showerhead as the first perc before the next larger perc. Although multiple showerhead percs are often stacked inside a single chamber, this makes the lower showerheads less effective because the airflow is distributed more heavily to the top showerheads. Honeycomb percolators are our favorite percs here at Stoner Pros. As disc percolators, they are small, easy to make, and take up very little vertical space. This means they’re cheap and you can fit a lot of them into a small vertical space. Additionally, they are one solid piece with no weak spots, which is why we recommend honeycomb percs with thicker (7mm+) pieces, as having a 2mm Tree Perc inside a 9mm tube completely defeats the purpose of 9mm glass. Honeycomb percs also pack a lot of punch in terms of percolator power. They can compete with, and beat, almost all other percolators in this arena. Finally, the numerous holes don’t create much drag, so you can consistently get a perfect hit without being slowed down. Depending on the size of the holes of the perc, water may sit on top, or always fall through just to pull water up through the perc when you hit the piece. As long as water flows through it, it doesn’t matter if water is sitting on top of it or not. Inline percolators are simple slitted tube percs, similar to downstems. However, unlike downstems they tend to sit flat in the water, whereas downstems typically enter the water at an angle, so they don’t have the problem of some slits being higher than others. This means the only limit to the number of slits is the length of the tube, which is why it’s fairly common for tubes using large inline percolators to be expanded horizontally, like the piece in the image on the left, to accomodate longer inline percs. Although this makes them more effective, the longer the perc, the easier it is to break. Much like showerhead percs, they are often used in stemless pieces as the first minor percolator which then leads to the first main percolator above it. Matrix percolators, sometimes called Birdcage, have become a lot more common lately. I normally wouldn’t give them their own category since they’re essentially the same as stacked showerhead percolators, but their prevalence has earned them their own category. They basically function the exact same way as a stack of showerhead percs.
Much like stacked showerheads, the top rows have less resistance and therefore make the lower holes less likely to pull any smoke through. This means that a one-row showerhead with more evenly distributed slits can be more effective than a matrix percolator with far more rows and holes. Even though they don’t provide any significant functional advantage, their aesthetic makes them desirable, as they appear to provide more percolation than they really do, although they still do an adequate job regardless. Turbine Percolators are another great disc percolator. Similar to honeycombs, their low height makes them easily stackable, and the fact that they are one solid piece makes them incredibly durable, not to mention easy to produce. The percolation power is similar to honeycomb percolators, however with larger and fewer holes, they provide a bit less percolation power. First, if you pull through them at the right speed you get beautiful cyclone effect, as seen on the left. The cyclone effect throws the water up along the edges of the piece rather than up through the middle, making turbine percolators function as effective splash guards, especially if the walls above the perc hit a ceiling where the tube turns into a smaller tube for inhaling the smoke.
Sometimes turbine percolators are used exclusively as splash guards and see little water pass through them, although we like to see at least a little bit of water goes through them both for the cyclone effect as well as the percolation power.