I have an i1-2 and use it for creating profiles for my HP LP2475w and get decent results and colors which match well with what I saw on my older (more narrow gamut) samsung display.
I'll probably try to borrow a spectrometer from someone to see how much difference it really makes vs. a colorimeter like the i1-2.
However there is also another problem I found with my new "wider than sRGB" gamut monitor Ever since I got it I noticed all my pictures on the web looked much more vibrant and saturated vs. my Photoshop color managed rendering. This is probably because the monitor has a wider gamut than sRGB, so the "uncolormanaged" browser was stretching the colors in my images over the whole monitor gamut, hence a saturation boost.
Today I found out that Mozilla Firefox 3 (my standard browser) has color management features, but they are disabled by default.
However if you look on this website
you'll find the background on color managed browsers and how to enable it in Mozilla Firefox.
I've just done it, and now my web published pictures look exactly like the same pic in Photoshop. So I now can also have more faith that pictures posted by others are rendered like they intended.
Maybe a bit off-topic but hopefully usefull for people getting wider gamut monitors.