I have the couchlog, both kinds of GTRs, a heat island, an Alpha+dog, a SC3 dog, and an enano, so I feel like I have a good perspective on this.
I would say that the Heat Island, SC3, and enano all have pretty similar profiles, being very enjoyable micro-to-medium-dosers, and I would rank them in the following order :
1. Heat Island
2. Underdog SC3
3. Enano
The Heat Island and the SC3 are more or less indistinguishable in terms of vapor, but I prefer the Heat Island's stems and construction (although it should be noted the stems are all interchangeable between these 3). The enano is a little more temperamental and harder to get a perfect roast dialed in, and I really dont like the chords and power supply of the enano relative to the generic chords you can buy for the UD and HI.
The Alpha+ dog's is basically the same design principles as the vapes in the paragraph above, but with a much bigger heater and longer airpath, so it feels more like at traditional log but with a lot more power. It takes a long time to get fully heat soaked (45 min-ish), but you can start to hit it around 20 minutes in, it will just have a bit more refractory time. After being fully heat soaked, I can take 4 or five full, huge bong rips before noticing any cool down. Its truly a beast, and I really enjoy this vape.
The GTRs and the Couchlog, while not similar to each other, represent a kind of next generation of the log vape that has emerged. As opposed to traditional log vapes with cartridge heaters, these vapes seek to create more potent heat stores, albeit through different means (The couchlog uses ceramic beads around the heater and the GTR has a SS foil insulation). The result of this is that, unlike the traditional vapes, where you slowly draw heat out of the cartridge, there is a more instantaneous heat transfer, allowing for more efficient extraction. There is room for both kinds of log vapes in my routine, as sometimes I prefer the less powerful sessions, but if you are only going to have one log I would definitely recommend one from this generation. Despite them all being very powerful log vapes, the couchlog and the GTRs are truly very different; hell, even the male and female GTR are super different, and they have the same heating element! It really all boils down to what you are looking for, if you want all the bells and whistles, I would say the couchlog is the most luxurious vape on the market, but if you want the best bang for your buck, whichever GTR best suits your use case is probably your best bet.
