I think they are both fantastic devices having owned multiple versions of both kinds.
The latest GG products are excellent for brand spanking new beginners because the main feature is versatility. Any battery, any atomizer, multiple voltages, etc. New features. New toys to try. AFS, etc. It's also nice looking while being very durable.
The SuperT products instead pick one "style" of vaping then do that style better (and thinner and lighter) than anyone else. Thinnest 10440 design, thinnest six volt design, thinnest cr123a design, etc. You also get nice things on certain models like adjustable airflow, and at this point I can not give up the adjustable button. It's also very durable, but very shiny. If you like shining things, this is the mod for you. The Super6 for me was the final mod once I figured out what I wanted in a mod. It lends itself to experienced vapors.
So in summary:
The GG philosophy is do a whole bunch of things very very well. Perfect for someone that likes that versatility and still isn't sure what their "ideal vape" is.
The SuperT philosophy is do one thing perfectly. Give that perfect platform for low or high volts, make it the best, make that platform itself highly adjustable.
The difference between a swiss army knife, and a perfectly balanced throwing knife.
hope this helps