Over the last few years companies such as Apple, Dell, BenQ etc. have been putting much brighter lights into their monitors - creating problems for those wanting to calibrate them down to typically recommended luminosities for print work. Some of them simply lack the controls to bring the brightness down below 250 candelas, which is ludicrously bright for day to day computer usage, let alone for colour accurate work.
Having a monitor that can reach a high brightness level is a good thing in some instances such as when watching a movie, but you also need to have the ability to bring the brightness down. Eizo monitors have the ability to easily reach the same high luminance figures as these monitors, and have excellent, precise controls for bringing the brightness down as well. In fact Eizo screens come with special software, ColorNavigator, that can detect which application you are running and dynamically switch between modes so that you can instantly take advantage of both high brightness levels when needed and lower brightness levels when needed - such as photo retouching.
You want your monitor to be the brightest thing in your field of vision when doing photographic retouching, but what's most important is the relative relationship between your ambient light level and the monitor luminosity.
If you own one of these new high brightness monitors, it's not all bad. There is in fact no absolute standard for where luminosity should be anyway. You do want your monitor to be the brightest thing in your field of vision when doing photographic retouching, but what's most important is the relative relationship between your ambient light level and the monitor luminosity. You can check this with the ambient light check feature if your screen calibrator has one.
Basically, should you own a screen that can't come down to normal figures like 120 candelas, this means you should keep your room a little lighter than is normal for this sort of work, which is not necessarily a bad thing. Ideally your room lighting level is 30 to 50% less bright than your monitor. This means your eye will calibrate to the monitor's whitepoint, as your eye always goes to the brightest white in its field of view and chromatically adapts to that whitepoint. If you get this relative relationship right, you should still find these monitors useful.
This, by the way, is why Colour Management works when your monitor has a whitepoint of 6500K and your print viewing lights are at 5000K, or less. In each case, your eye auto adapts to the whitepoint and it's how colour behaves relative to that whitepoint that is important. If you had the light levels equal, and were doing side by side matching, you'd be better off calibrating your monitor to the same white point as your lighting (i.e. around 5000K). This is not recommended though as it takes you well away from the monitor's native whitepoint, and there's a big price to pay for that on an LCD as it tends to promote pretty severe stepping across the gamut.
If photographic retouching is a big part of what you do, or simply if you spend a long time in front of your computer on a regular basis, staring all day into 250 plus cd/m2 can be very tiring on the eyes, and personally I'd look to a better screen as a possible future purchase.