found this on gamutprints.com
XRite DTP-94 – Of the bunch this tends to be the most consistent and most accurate, especially with regards to shadow detail however when used on wide gamut displays, and displays that use white LED backlights (most laptops, all current Apple products, and most consumer grade monitors that are currently being sold) the results from the DTP-94 are inconsistent from profile to profile. We only recommend this puck for use with screens that cover the sRGB gamut.
X-Rite i1Display 2 – This was probably the most popular unit on the market. While not quite as accurate as the DTP-94 this is a good all around colorimeter however, like the DTP94, this colorimeter struggles with screens that use LED backlights, or that cover a wide gamut. If you already have an i1Display 2 we only recommend using it for standard gamut monitors that use CCFL backlights. This colorimeter does not yield accurate results with wide gamut monitors, or with monitors that use white LED backlights. If you’re in the market for a colorimeter you will still find it in the retail chain however we do not recommend buying it (even at a discount) as it’s been discontinued and replaced with the i1Display Pro which is a by far, a much better package (as one would expect after 7ish years of development).