If you check out any of the major addon sites, you will more than likely find an older version, one that still functions, so it might suit your needs. If you want the most recent version, the WoW Ace Files site has the continuously updated version.
To open the configuration window for Quartz, use the following slash command:
This will open up the options interface, where you can change the cast bars to your liking. One feature I found nice was the Merge Tradeskill option, which will take multiple casts of the same tradeskill and puts them into one cast bar, with a countdown timer. I like to know how much time I have to run and grab a beer when creating what seems like a thousand bandages. This addon also creates new cast bars for your target and focus, as well as showing buffs and debuffs, with timers. Configured correctly, this can keep a lot of important information in a small area.
Quartz will also work with FlightMap, FuBar-ToFu or InFlight to show a visual timer when flying in game. Once again, it's great to have a visual cue for that next brew. It also adds some cast bars for some other events, like arena game starts and party invites.
Casting bars are recolored if your target moves out of range, if you are interrupted and adds a latency bar to help you time your next spell or action. The swing timer is nice, mostly when I'm trying to time a well-placed Crusader Strikes between swings of my Hatebringer. (I love it just for its name.)
Quartz does not do anything that I would consider absolutely vital to my own game play, but it brings some great features that I find visually appealing and useful. Some people swear by it, or something similar, so take this one out to the range and run some rounds through it. Dismissed!