With any bike your experience is going to be better if you understand how it works a bit better. youtube tutorials, sheldonbrown.com, park tool website: there are lots of resources to look through. If you can adjust your derailer yourself, you'll like the bike a lot more. That said, if the bike sucks and the components suck, your experience with it will suck as well, no matter how good you are with a wrench.

fixed gear bikes are a lot more simple, and in terms of daily riding without worrying about stuff like ball bearings, there is little maintenance. With a decent road bike with decent components, there is a little more, but once everything is adjusted correctly, it should stay adjusted for a while and also require low maintenance. Fixies by default win the maintenance comparison.

You're only as fast as your legs and lungs, on any bike.

comfort can be customised on any bike as long as the bike fits. saddle, saddle height, bar type, bar height, these are things that apply to both fixies and geared bikes.

This is all my opinion, but I will say I only fell in love with bikes once I got an old 80's road bike to replace my crappy mountain bike, which kept missing gears and having a lot of problems.


PS::
you mentioned conversion. In my opinion, if you dont know anything about bike mechanics, I'd hold off on a conversion, sell your current ride and use that to finance the purchase of a new fixed gear if you decide fixed is for you.