i have the bell city. same shape as metro, same strap, visor. i use a zip tie to hang a taillight. i have a headlamp duct taped on as well. use a cycleaware reflex mirror, much better that the crappy one on the metro. i got the citi for ~35.
funny thing is, straps on my 5 year old bell are better. the front strap attachement point is further forward than the city/metro, giving more secure fit. less likely to flip up and rip off your head.
big safety feature of the metro/city is supposed the lack of aero pointy design on rear. the rounded, more form fitting shape supposedly works better in a fall (go to the helmet tester org site, cant remember acronym, they had a little comment on the metro/city).
dont know what that round rear means on a practical level, because it still feels the same when your noggin hits the road. guess you gotta hit it with more energy than i normally carry.
and there are fewer vents, so its gonna be hotter.
i dont think any helmet is worth more than 30-40 bucks. probably those 18 dollar walmart bells are the best deal (none in my size when i bought last one, mostly kiddie size).