Welcome, For clouds you will want a high voltage device. For a noobie with potential i wouldn't go for anything less then 100watts to start off. or you could go with a unregulated mechanical mod if you don't mind swapping batteries often. I would personally go for a mod that holds the most amount of batteries, but that's just me.
Some popular RDA's are Twissted messes, velocity, mutation. But don't get too hung up on atties. Juice and Perfect coil builds we be the bigger determining factors.