I had similar questions when I built my bike last year. I put eggbeaters on it, although I had no previous clipless experience. 16 months of commuting later, conclusions;
- clipless pedals make a night and day difference. The single biggest improvement to my over-all cycling experience.
- eggbeaters, for a number of reasons, are not suitable for riding fixed. They are just not secure enough. The cleats are too soft and wear too fast. Around 6 weeks after installing new cleats (each time) they start disengaging under load, eg. leaving traffic lights or slowing up. I tried adjusting them, but can't do that any more, having scuffed the ends on a few curbs. They're light and look interesting but aren't up for the job. I've switched to Shimano SPD m520s; heavy, clunky, but better fit for purpose. Might have to switch to a proper road pedal system next.
- I'm safer riding fixed. No tumbles or accidents in the last 16 months (several in the previous few years). Lots of possible explanations. *shrug*
- I used to get through a set of brake pads every 3 months. I'm still on the first set on my fixed gear.
- As they say, riding fixed is an engaging experience. More tiring perhaps, till your muscles adjust, but fun. I love it.
- I just built myself a racing bike - now I'm struggling to adjust to these weird gear things and the freewheel. Ugh, I loose contact with the bike when I stop pedaling!