I have a 505 with the lightwedge and my husband has a 700. I'm very happy with my 505/lightwedge combo--and prefer reading on it to my husband's 700.
Most of my reading is done in well lighted situations, and I simply flip the lightwedge to the left--holding the reader case like a hardback book. I actually like the added weight of the light wedge--makes the reader a little more substantial. When I'm using the light, I bend the cover all the way around so that the two sides are next to each other.
One other benefit I find is that the batteries in my reader last a lot longer than my husband's. I use rechargeable batteries in the light wedge and am able to go quite a while without recharging them.
Now, on the other hand, my husband is perfectly happy with his 700 and wouldn't trade with me. (He reads a lot more technical books and makes good use of the search and zoom features.)
Good luck with your decision!
dordale