I have Evods, Aro's, Protanks, and the top-coil Vivi Nova. Haven't tried the iClear but have considered the iClear30s which I think is a bit different. Anyway, having tried both top coil and bottom coil here is my opinion.
I like the ease of use and consistency of the bottom coils. I started with evods and have been very happy with them. I recently was sent some Vivi Nova 3mL tanks and I fell in love with the warmer vape and fuller flavor, but I find the coil cleaning and "swishing" aspect a bit of a pain. I also seemed to get dry hits or bad flavored drags every now and then, even when making sure the wicks were fully saturated. Funnily enough, I also get that from my protanks, and I don't really use them anymore because of that (and the "gurgle" factor). Never got any of this from the evods, or the Aro.
If someone could harness the warmth and flavor from the top coil with the ease of use and consistency of the bottom coil, I would be ecstatic.