I have the isub G and it's a pretty nice tank, I do find that it leaks at times if you're not careful about putting both bottom sections together just right. I purchased the isub G in a kit with the mpv 3 pro which is a very nice mod, 5 watts to 60 watts.
Most of the time today I use the Hercules sub ohm tank by sense. I use it at 60 watts normally, great clouds, flavor, etc. and I'm extremely satisfied with it. The mod I use with it is the Snow Wolf 200 which is great just a little clunky. If I need to save battery life I drop the Hercules down to 42 watts, nice cool vape/smoke. Price is great at around $20, no leaking, only drawback is it's only a 3ml tank, talk of a 5ml soon.