I have a Topside and I love it, but you really won’t benefit from using it with a sub ohm. Plus, it’s bigger than a regular single battery mod, because of the
juice bottle.
I would not recommend starting off building RDAs either. But yeah, better flavor.
I’d say get one of those Aegis and a decent
tank and start there.
Learn your vape style, and then if you’re interested, learn how to build to suit your preferences. Doing it the other way around works for a few, but it makes things more difficult for you.