more expensive calibrating gear is more accurate, but its impossible to get a 100% accuracy match from external LCD monitor to a laptop monitor - regardless of how well you do it.
The only way to get every single monitor to match 100% is to use the same monitors. Each monitor has different characteristics in colour gradations and hue and etc.
For example, a Dell U2311 wil be slightly different to the 27 incher even if everything is all equal in values and settings.