I've taken them off all of my bikes. They are eye catching but I have gone to relying mainly on active lighting for night time visibility. With the advent of high output LEDs and USB rechargable batteries, active lighting has become very practical and economical. I have a bright red multi-led blinking light (two on my touring mutt, one on each seat stay) in the back which is visible from 180 degrees. On the front I have a 240 lumen LED flashlight in a Fenix handlebar mount. It has high, low and flashing settings and is easily visible from a mile away and gives me a clear view of 100 yards or so, even further for reflective objects. I haven't forgone reflectors altogether though. There are lots of alternatives to the afterthought, minimum required by law for retail sale, reflectors that come with bikes. Here are a few of your options:

- There are retroreflectives tapes and pre-cut stickers in a wide variety of colors, including black, that blend with your gear, helmet, frame or whatever by day but that reflect headlights or streetlights at night.
- If you use dual sided pedals, there are low profile reflector kits that don't interfere with clipping in or out and are unobtrusive (at least no more obtrusive than a dual sided pedal) during the daytime.
- Reflective spoke covers snap in place and are easily removable later. You don't have to cover every spoke, two-inch sections on the rim ends of two or four opposing spoke pairs will provide plenty of motion.
- Several companies have tires that have reflective lines on the sidewalls. Nothing says "bicycle" like two big circles crossing the road ahead.
- Mavic has introduced rims with retroreflective finishes. Ditto on the two big circles thing.
- There is a retroreflective spray paint available in both permanent and temporary versions which is said to work on both equipment and clothing (I haven't tried it nor seen it in person, but the online videos are impressive)
- Many helmets and some other equipment, like gloves, have reflective elements.
- Bright/light colored clothing with 3M reflective dots, stripes, etc. is an alternative to permanent or semi-permanent elements on your bike as are reflective wrist and/or ankle bands. I keep a pair of velcro ankle bands wrapped around the outside of my seat bag in case I get stuck out after dark unexpectedly.