Be aware that the dyes in the filters of colorimeters degrade with time. You might find that your Eye-One isn't as accurate as it used to be. Also, the Eye-One doesn't have a wide enough colour space to calibrate/profile accurately wide-gamut monitors. You might want to think about replacing it at some point.
I have an Eye One Pro Rev. A I bought in 2004. This week-end, I started to explore ArgyllCMS to create printer profiles. This has showed me that my old Eye One is working fine. With it and ArgyllCMS I can produce profiles that are marginally better then an Epson one (Premium Luster) and visibly better than an Ilford one (Fiber Gold Silk), especially for B&W printing. In both cases, shadow separation is better with my profile. I also successfully profile Hahnemühle Baryta Fine Art, again marginally better than the profile from Hahnemühle.
So, after 10 years, I see no reason to replace it. I recently acquired an i1Display Pro 2 for display calibration and profiling, though. The provided software is a real let down, including for the quality of the profiles, but with DispcalGUI the result is fantastic.
I am returning a Datacolor SpyderStudio that I wanted to test against my new and old X-Rite units. For screen profiling, there is not much between the 2 solutions. Both work much better with DispCalGUI, giving results I cannot distinguish. For print, the Datacolor solution is workable, but very tedious in the measurement phase. You have to be extra careful and measure spot by spot to get enough precision. ArgyllCMS with my old Eye One Pro is more convenient and produces better profiles.