Beck gives the nod to the Igo-S, nice.
OP: regarding your lack of draw, gurgling, no flavor, etc. you have some flooding going on for sure. The tip it on its head trick works but I think you are beyond that at this point. You need to stand it on it's head and unscrew the coil head base, then carefully unscrew the head from the base, wipe it all down really well, now you have three options.
Opt 1- you can simply put it back together and see how it goes.
Opt 2- screw the head back into the base and attache just that part (no tank with juice) to your battery. Now you pulse the battery until you "dry burn" the coils which will cook some of the built up stuff off the coils. Once this is completed you can put it all back together and give that a shot.
Opt 3- same as Opt 2 but you need to wash out and dry the coil head before the dry burn and reassembling the atty.
Keep in mind that Kanger tanks don't like to be squashed so you can't crank them super tight to your battery. There are a series of rubber spacers in the heads that, if squashed, will cause leaking.
Hope this helps, sounds more complicated than it is.