The biggest difference between the GR2's and the Tokico illuminas is that the illuminas are adjustable.
If you can afford the adjustables, they are definately worth the money. Like Jeff said, the KYB AGX and the Tokico Illuminas are both really nice adjustable struts. The AGX are usually about $100 cheaper, but are only 4-way adjustable (instead of 5), and seam to be a bit more stiff.
I had the Tokico Illuminas, with H&R springs on my '91 turbo, and it was a real nice ride. Pretty comfy on the soft setting, with 5 way adjustability for autox days.
I had the GR2's in my celica. They are great for the price. Just a little bit stiffer than stock. I'd say if you want a little bit stiffer ride and are on a budget, go with the GR2's, but if you can spend a little more, the adjustable struts are definately a worthwhile purchase.
Just my $0.02