Bricca - thank you for asking. I am still a big fan of the Merkava for the flavor. I've found the flavor is better on many of the pastry type e-liquids I vape and really good on the tobacco flavors, too. It is one that I use every day. For MTL, I think the Eviva-T supports that style of vaping better, having a tighter draw. Even on the smallest AF settings, I find it fairly easy to do LH with the Merkava. I can do that on the Eviva-T, too, but at a much slower rate.
While I like the flavor I get from the Eviva, I'm not a fan of trying to build in the ceramic cup - I prefer a larger diameter coil (2.5-3mm) and it is difficult to build that in the Eviva. With the Merkava, I can build a larger coil, but to do so, the coil is raised and has to be lowered after attachment to the base. I finally saw a video showing someone using an hex key to push the coil down (since I use ni200 in the Merkava, my previous attempts usually ended with me making a mess). My wicking is fairly straight-forward and I haven't had any issues with dry hits (unless I forget to set the juice control). The same is true about refilling - no issues unless I forget to close the juice control. I've vaped 50/50 VG/PG and max VG without issues.
In my experience, juice consumption is really good, but not as good as the Gem, which is the best I've seen in my limited experience. With a 5ML capacity in the steel tank, I seem to be able to use it all day without refilling - but this isn't the only RTA I am using all day, either.
I have the Squape R (well, had - my wife has decided that she needs it more than I do, which was ok because it allowed me to pick up several other atomizers like the Merkava and Ubertoot), Taifun gt2, Gem, Phenomenon, Aqua v2, Kayfun V4, etc. To me, the Merkava has better flavor than the Squape, Taifun, Aqua, and Kayfun V4. But, I also think the Kayfun Lite+ has better flavor than these. I'm just not a fan of the tool needed to refill (and I know they have accessories to make than unnecessary) and I've become more of a DLH vaper than a MTL.
I apologize that this is so long and wish I had more experience in being able to provide you with the information you want. This is one of 3 RTAs that I use every day (since I started using it consistently - approximately 1 month). If you get one (and it appears that they are currently out of stock on the mini-ecig site), be sure that you thoroughly clean it. I did a rush job as I was anxious and had a bad experience with the first tank. After I carefully cleaned it, I've really had no issues.