While AROS is my "NG amiga" platform, and what I use mostly these days, I actually voted for classic as the question asks, "which software is cooler" and mentions nothing of your preferred platform.
While for basic usage most of the "NG" platforms is covered, and there's some effective software for them, there's not a lot that stands out as "cool" to me yet, but rather functional. The software available to the amiga in it's heyday was as much a reason for my interest in it as anything else. Im a creative person and people invested time, money and energy into untapping the amiga's power, power that had seldom been seen before in home computing, so interesting software was created. OS4.x, MOS, and to a lesser degree AROS are still way behind the curve technology wise, and they're not generating the sort of interest that brings time and money to create interesting software that lends itself well to them, so we get mostly small tools or ports from the open source world. Good things, and appreciated, but seldom do these sorts of thing have the same charm/coolness about them.
Now as for why I chose AROS, originally price and availability, but after a while the journey, the highs and lows, become a part of it. Additionally, in the current computer world landscape it's the only one I see as having a genuine chance of surviving and/or prospering, plus you really do get used to the extra speed. Often I'll play a dvd as background noise while using 68k software that uses AGA. Or browse with multiple instances of OWB, each with multiple tabs while wookiechat is running while playing music and using lightwave (both random examples).... you know the sort of "normal" stuff people do on modern computers. Throw in the fact there's a lot of ocs/ecs software that I'd like to use regardless of platform and AROS is the only amiga system that allows me to continue with this uncompromised. Sure it's a little behind in some areas and lacks a few bits of software compared to MOS/OS4.x, but I'm willing to wait.
Technical perks/quirks aside though, the fact that I can completely and utterly customise it to my hearts content is a factor for me too. If there's something I dont like or something I consider missing I can simply change/fix it myself, or try to persuade someone into doing it for me if I dont have the skills :-)
