Although new to the process of rebuilding RDA's, my impression is that the hardware effects more of the ease of build and airflow options, while your actual build effects vapour production and performance.
I am currently using the IGO-W with a single 1.8ohm coil and cotton yarn wick. Really performing nicely. The IGO was easy to setup with the hole guides in the posts I didn't have to wrap the wires around a screw, and the Phillips screws in the post are secure so no sliding around. You are stuck with the stock airflow but there is 2 holes in the unit, I don't really find it an issue, but I've seen some build videos and lots of people drill it out to get an airier draw.
I do have a Trident clone coming in the mail, I'm really excited about the adjustable airflow, but not the flathead screws, but that's a minor worry.
I was having a IGO build discussion with someone in a different forum, and in a roundabout way, we came to the conclusion that if you're using a VV/VW battery, you're probably better off building a single coil, whereas if you have a mech mod it's opportune for the dual coils. Once you double your coils, you drop ohm load in half (two 2ohm coils will read out as 1ohm), which may be difficult for some variable devices to fire optimally.
If I get a chance, I'll post my Trident findings here for you to peruse. I have a feeling it's going to be a few weeks until I see it though.