I carried a zytel Endura for five years of HARD carry, broke the blade and reground it three times. It still is totally servicable, except the I broke the zytel clip. I recomend the newer model with the metal clip if you get zytel, much more durable. As for the steel, is looks great and feels like it is indestructable. But, is slippery and heavy. The zytel is so light you won't know you have it. Another thing about steel is that it looks fantastic when you get and after one carry, it will have scratches all over it.
G-10 and Micarta offer the good looks, toughness and durability without adding the weight, but are more expensive. I have owned one of almost every production knife and I always pick up a spyderco when there is actual work to be done, I am not even sure why. They are just more of working knife than most I guess. My EDC right now is a steel Spyderco Co pilot attatched to a Arc AAA.