With regulated mods, I like simple elegance. No lights, voice commands, talking mods, or designs and color schemes I would find in a child's toy box. Number of batteries and size would depend on what I want to put on it.
With mechs, I want small, compact, single cell squonks. I don't care for tube mods much, and with my vape style, multi battery mechs are overkill.
With RDAs, I look for small, compact, reduced chamber 22mm RDAs with restricted airflow. Crazy engravings and tons of words or designs just clutter up the device and detract from the looks in my opinion. I also don't care for proprietary drip tips or big 810s.
With RTAs, I look for good capacity, replacement tank availability, simplistic airflow, and well thought out wicking ports. No gimmick decks, airflow, or fill methods.
My biggest pet peeve in the vape world is how often a new product is instantly idolized as the new greatest thing ever made in the vaping industry, until two weeks later when another new product comes out and takes over that claim. Really makes it hard to find what is truely great.