I haven't had a chance to play with one yet, but since it works within Versaworks, it's not going to be able to create a profile, but it will let you calibrate your profile - which in my opinion gives you the biggest bang for your buck as far as gray balance goes. It will also allow you to calibrate multiple similar printers to each other giving you more consistent output across your various Roland printers.
$500 is a third the price of an i1 and you'd need to add software to create profiles which would add another grand to the price - then there's training.
If you're a Roland shop, and want to tighten up your color quality, then I think this is a good step in the right direction at a reasonable price.
Good Luck