Picking an RDA is very subjective to the user. The Nixon seems to get great
reviews on flavor, and a bit better than the freakshow mini. You are in the stage right now where you are finding what works best for you, just be sure to always be safe with your builds, and check them on a DMM or a dedicated Ohm reader before firing them on your SMPL mod that you noted in another thread that you picked up. Also be sure that the 510 Pin on the Nixon protrudes AT LEAST 1MM from the base, anything less than this is unsafe to use on a SMPL mod as it is a Faux Hybrid, or Direct to Battery Mod. Be certain also not to build at too low of a resistance, as not to exceed the CDR of your batteries.
You are going to find it will take you a few purchases to really settle onto what suits you best. So if the nixon turns out to be less than impressive to you, dont get discouraged as this is all a journey of finding what is best for your tastes and needs.
Either way you would be getting a good, budget friendly RDA, with bottom airflow. The Nixon seems to be king for flavor, while the freakshow mini tends to be a bit more airy and cloud chasing friendly.