everybody got different preferences in regards of what device they use.
RDA is good because of the ease of building (coiling and especially wicking), there's much bigger margin for error in an RDA, at least in my experience. And the flavor production from high quality RDAs are top notch. the downside (subjective) you'll constantly drip, it's really not practical if you're a busy person and constantly being out and about.
RTA has the advantage of liquid capacity, you dont have to constantly drip, fill the tank and youre good to go, the downside is most RTAs are really finicky to wick, wick it wrong and you'll get leaking.
RDTA, i really dont like RDTAs, so I cant comment much on these.
just my 2 cents.