We love us the shiny-shiny, and it's hard to beat the look, feel and sound of new climbing hardware. Black Diamond knows of our addiction and feeds the habit with their Ultralight Camalots, improving on the standard version in all areas except, alas, cost.
Regular Camalots are still available, and in a slightly greater range than the newer Ultralights. The two models overlap in seven sizes: .4, .5, .75, 1, 2, 3 and 4. If you need smaller you can step down to the X4 line, also available in some offset sizes. If you need smaller still you can go to the C3 three-lobe line, and of course there are color matched Neutrino wiregate carabiners if you're getting your full OCD on. But we digress.
The Ultralights are the same awesomeness you've always loved in the standard Camalots, but lighter, saving you anywhere from 0.78 ounces for the .4 to a full 2.26 ounces for the big gun 4, with the intermediate sizes being around an ounce savings each. The savings is achieved through more aggressive cutouts and by replacing the metal cable with Dyneema. This results in a very small strength reduction of 2kN for each size, to 8kN-12kN, down from 10kN-14kN for the standard model, which should never be an issue.
The feel is noticeably lighter for the larger sizes, and otherwise identical in terms of trigger and placement. Very solid, very satisfying, very safe. So here's the thing: unless you have extra money and/or a real need for weight savings on your rack, you can stick with the regular Camalots and save a lot of money and/or buy more cams. To put it in perspective, if your rack had one of each of the seven sizes it would cost about $500 for a rack of regular Camalots (total weight about 38 ounces) and $700 for a rack of the Ultralights (total weight about 30 ounces). You can save eight ounces or $200, or you can buy two or three more cams for the same amount of money. Again, both models are friggin' awesome, just do the math and make good choices!