Very solid material, much better than I expected. Also sleeved them up, simply to be able to write 'my' casting value on it, with a wipeable cd/dvd marker. Obviously not cheap as such, but you get 80 cards for that money (81 actually, there's an extra one explaining the symbols used for the different schools of magic).
Do they add to the game experience? I previously used cut-outs fromt he downloadable spell sheet, so that I had a quick overview of all the spells I had, including their full effects (certainly beats having to get your book all the time). These are obviously similar, but better looking, stronger and don't require you to cut 80 rectangles spread over 10 sheets of paper...