How big are your batches?
i have two chillers. The Stasis is probably the least expensive chiller on the market and can chill two 5- or 6-gallon batches simultaneously. It has built-in pumps and thermostats, which is important to consider when comparing cost. Most others don’t come with those. Its main limitations are a fixed glycol temperature and small pumps which don’t seem to be able to handle much head pressure, so I try to keep the chiller and fermenter on roughly the same plane. Some say it is very loud. I wouldn’t want one in my living room, that’s for sure, but it’s not offensive. If you define cold-crashing as 33F, the Stasis is not for you. It struggles to get to the advertised 36F.
I also have the smallest Penguin. It appears to be a repurposed window air conditioner. The case is really strange. The bottom isn’t flat and it lacks any feet. Mine is sitting on a rolling furniture dolly. The reservoir is a bin with what appears to be a plastic food service tray lid that has had holes drilled through it for the cheap plastic hose barbs and pump wires. The smaller Penguin pumps are quite strong. It can have up to four pumps, but I have just two and think that getting two more pumps into that reservoir looks like a bit of a challenge. It is quieter than the Stasis, but not dramatically so. With greater capacity and an adjustable glycol temperature (using one of those inexpensive temperature controllers that require a manual to operate...Ugh), it can cold crash to 33F or even lower.
The Penguin is more functional than the Stasis and Penguin’s support is quite a bit better. I suspect that Craft-a-Brew’s staff is all part-timers who also have full-time jobs. That’s pure, unadulterated speculation, though. It has taken me days or even weeks to get a response from Craft-a-Brew and responses have sometimes come at odd hours of the day. But as I’ve become more familiar with the Stasis, I realize that it meets 95% of my needs, is relatively low-cost, and has a desirable small and light form factor, plus greater ease of use. In short, both are good, but imperfect.
People seem very satisfied with the Icemaster units, but I have no personal knowledge of them.