I'll bite... I'm a noob at this though.
There probably is an easier radio to learn on, but if you want the 8r go for it. I learned on a 2m AA battery radio shack radio first which was pretty basic
http://www.eham.net/reviews/detail/425 but not very easy to use, and then got the opportunity to use a Kenwood D-710 for a while, which was really really simple and does a lot of cool stuff
http://www.eham.net/reviews/detail/6871.
If you could get a loaner radio first that would be best. You may decide that you might like a mobile or base station better (which are much more powerful and can usually interface with a computer pretty easily), and can live with a (a lot cheaper) basic but still capable
HT Kenwood TH-F6A Amateur Radio HT THF6. Look around the interweb and pick the price you are willing to pay and go from there. An
HT for the first radio sounds cool because you can go hang out a the coffee shop while you figure out the
HT and ham radio in general. What I
am getting at is, if you get the 8R (pricey) you will be reluctant to get something else more powerful/features later because the 8R already took a chunk out of your wallet and does quite a bit (aprs, submersible...). In retrospect, I think I could do OK with a vx-6r/7r or the th-f6a
HT and with the money I wouldn't have spent on the 8r (and all of the accessories) I would have got the kenwood d-710 mobile.
If you have your eye set on the 8r for some reason you should get it, but I don't think playing with it before your test is going to do much good. It could help, but don't wait for it, just take the test asap so you can start playing with any radio you can find.
-vvt