I've got one of the mini RDAs. It's a better match for ego size devices IMO. I dunno why StarDose says you have to mod it. There are tons of different ways to build a coil, and I believe that's the most important part. Sure you can drill out the hole to get more airflow, or stuff more wick into an RDA with a recessed bottom to hold more juice, but if you just wanna be able to switch from flavor to flavor without filling a whole tank, a short wick and a simple coil is all you need.
You will need to get some way to test resistance tho, so you can figure out what works best for you with your setup and so you can make sure you aren't under 1.5 ohms (which would possibly wreck your battery). For me, I aim for 1.8 to 2.0 ohms (4/5 wrap of 32 gauge kanthal on a 3mm wick usually does the trick). If you really get into it you'll probably want some sort of variable voltage (or variable wattage) device. You might even get into mechanical mods and sub-ohm coil builds (just make sure you read up on and understand all the safety precautions). Or you may be perfectly happy with a 2 ohm build on your Evod battery. It's a whole other way to vape. You can get as deep into it as you want or keep it as simple as buying the prebuilt replacement wicks, but once you learn how easy it is to make your own I don't see why anyone buys premade!