Re: DiamondBrite vs. Pebbletech vs. other exposed aggregate finishes (there are many).
Today they all perform well, differences are how they look, how much they cost, and how they feel on your feet. The last two criteria are often the most important! If you can, find a pool with the finish you are interested in and try walking on it. Some of the quarts aggregates are very rough to walk on. These finishes are just sand, pebbles, or crushed quartz in a plaster.
Also, there is nothing wrong with a marcite (plaster)finish. They are generally less expensive but not really less durable then the aggregates if properly cared for and can be done in many colors besides just white (although I prefer white plaster myself).