Many people who know my work know that most of it incorporates the use of photopolymer printing plates. I design an image or text on Adobe Illustrator, then using a uv light, I expose the image onto a photopolymer plate, essentially making my own mold.
I have used 100's of plates in the past...plastic backed, metal backed, shallow, deep, etc and BY FAR the best product IMHO is the metal backed plates sold by Tonya Davidson at Whole Lotta Whimsy http://www.wholelottawhimsy.com/. And, she is such an awesome supplier that she now sells them in larger sheets so you can save some money and cut your own. I go through 100's of these, so this has been a huge help.
For years I used the plastic backed plates. They are great and cost-effective, but no matter how you store them, they will eventually bend and crack. I then purchased a bunch of metal backed ones from Boxcar Press. These were great, nice and flat, but for some reason they just aren't as much of a pleasure to work with as Tonya's....more difficult to wash away, etc. Tonya's are quick, and will hold incredibly fine lines. I have heard people say you can't go below 1 pt with text, but I have made a plate with a .25 pt line and it was breezy and easy (Cover Girl?:))