The one thing that no one has mentioned is that the best lighting is always in layers. I would never have just can lights in my bedroom. Can lights / down lights are usually used for general lighting, not task lighting. Bedside lamps or wall sconces are an additional layer that provide low levels of light for reading at night or when low level lighting is needed. The other thing to remember is most of the time when you are in your bedroom, your eyes are closed.
No one ever wants to walk into a dimly lit bedroom, think ceiling fan/ light combo with "soft white" incandescent lamps. You also don't want to be blinded either. However, dimming the amount of light is usually much easier and cheaper than trying to add additional light fixtures.
I wouldn't rule out using can lights in my bedroom, but I also wouldn't want it as my only source of light in the bedroom.
I also don't agree with Renovator8's comment about the trim size for cans. A 6" can is the most commonly sized down light. Most builders use them because they are common and therefore cheap. They can designed for most common household lamps including both PAR, R style, and "A" style lamps. "A" style lamps are the pear shaped incandescent lamps that most people refer to as bulbs or lamps for their home. An "A" lamp does a great shop of spreading light, but not at delivering it. Most of the light is usually lost within the fixture. Many builders use PAR or R style lamps because due to the way the lamps are shaped, most of the light is delivered to the work space and has a decent spread. If a lamp or bulb is seen from below the ceiling plane, then two things are going on. One - the can light is cheap and not deep enough. Or two (more likely) - someone is using a lamp that is not designed for this fixture. This can be a compact fluorescent "Par" style lamp or a larger wattage R or PAR lamp. Either way, the fixture is not being used as intended.
Most manufacturers of down lights have a wattage label inside the housing, but there should also be a sticker on the trim indicating the correct style of lamps to use. Whether or not someone pays attention to it is another matter.
I'll get off my soapbox now.
FYI - I'm a manufacturer's rep of over 100 different commercial and residential lighting lines. All I do every day is sell light fixtures and look at different lamps.
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