You really don't need much to get good clouds from an even decent RDA; you just have to build accordingly. I get great clouds from my teeny little iStick 30W building 1.2ohm duals with a large surface area on a good Tugboat clone, opening the airflow, and setting the watts around 25-28. Are the clouds as big as those I can get on my mechs with a crazy subohm build? No, but it's more than adequate for normal use, and it's 20W less than what you're asking.
In the future it would help if you could provide a little information in your posts because we have no way to know yet what you're really after. Vapor production is not solely dependent on wattage. It comes from a variety of factors not limited to your build, surface area, wicking technique, which RDA you're using, how much airflow it has, your mod, etc. There's a lot more to it than how much power you're running, so please make sure you do your research.
But if you're looking at a device, 50W is plenty. If you get really into it, the ability to go up to at least 100W isn't a bad thing, even for rare occasions, but that's really not beginner stuff. In my not-so-humble opinion, a person should make absolutely certain they are good at building coils at a reasonable resistance (say, .9-1.5 or higher) before delving into crazing sub-ohm stuff and you can absolutely get clouds (bro) doing so. 50W is enough for that, but you may ultimately find yourself wanting more sometimes.
Be safe.