I have the VTR and I would go with the other thing. The VTR can fire 0.6ohm coils (or at least mine can), but the power output is very limiting, especially if you want to run a dual coil RDA.
It is also quite expensive compared to the more recent VW devices which offer more power. It is nearly a pound in weight too, so if you are carrying it around in your pocket then make sure you are wearing a good belt, I have lost count of the number of times that it has taken my jeans southwards, sadly the police are better at keeping count of it.
It is a solid build, but as anumber1 mentioned the ring is a limiting factor to consider. Having to use the extension piece is a serious design downfall. I did carve out the ring to fit my Kayfuns, but I find that the best use of a VTR is to build muscle whilst you vape, just remember to switch arms!