My top RDA is the Trident V2 right now, very solid. It just went on sale at Fasttech recently, but you can get it stateside for about $10 more, give or take, and have it within a few days. I also really dig my Helios, it's contending for top spot and is a strong contender. (Make sure it has two holes on both sides, not the one that has just one side with two holes.) Both can be found on eBay in the $20-25ish range.
The main difference is with a dripper, you have to top up every dozen or so puffs with about 10-15 drops of liquid. That's fine for me when I'm just chilling, but I wouldn't want to drip while I'm driving or working myself. (Thus I run Kangers too, they're a bit easier to run than KFL's and the like...but I'm a field guy and size/convenience/ease of use matters to me.) I personally seem to prefer my RDA's over RBA's/RTA's, mainly because I like to change it up quite often.
After awhile, you can get pretty good at those Kangers and practically do them in your sleep. When you get into microcoiling them, it's nice to be able to switch out the wick pretty easily every week or so to maintain the top flavor. I would say do them a few dozen more times and you'll get a lot more comfortable with them.