I'm for the Pro-10, and absolutely love it!
The longer-lasting pigment inks on the -10 cost more (by about 15-20%).
The dye-based inks on the -100 tend to be slightly more saturated (especially the reds). However, since they fade faster, especially if in a sun-lit room that is quite bright, they will match the pigment version's colors in a few years, and "fade-away" after that.
Note, however, that the newer dye-based inks are quite good (be they Canon or Epson), and "fade faster" still may mean decades instead of months, as was expected only ten or fifteen years ago.
And, most importantly, the proper care, display, and handling of *any* print you do with either of the -10 or -100 will extend its life considerably.
If the *cost* of a print is a concern - a 13x19 from either one of the Canons will be in the vicinity of two or three dollars each, for the ink alone - and you could spend as much as four or five dollars for a really good "fine art" paper. The Pro-1000 and its much larger tanks is roughly one-half of the ink cost of either one. So is the initial cost*, but then you'll be able to print those 16x20s to your heart's desire.
You should check out the Red River site. Some very good info there, as well as quality products.
http://www.redrivercatalog.com*Right now, with sales and rebates the -100 is virtually free, the -10 is around $400 to $500, and the -1000 is about $900 to a grand.
Good luck, and I hope I didn't murky the water too much.