I've been fooling around with all 3 and just ran the benchmarks for comparison. I generally default to Safari for it's better integration with OS X, builtin Facebook and Twitter, and iCloud syncing. I don't open a slew of tabs or windows, and i use minimal plugins... Flash, Java, QT, and Reader. I haven't had a crash from either of them in a long time but I have a few niggles with each of them.
Firefox 'feels' the slowest and I've run into a few rendering errors and page hangs. I also don't like it's print dialog... no preview and it prints smaller than the others. Java will spike the CPU to 100% and hover at 65%, and the only crashes I've had were on Java sites. I've also had RAM usage creep up to 1Gb over extended use. The WebGL Aquarium test brought it to it's knees and it didn't display the Peacekeeper WebGL test properly. It supports trackpad swipes for back pages but not zoom.
Chrome is fast but the cost of that is increased battery drain and warmer CPU. The multiple process Chrome uses may be more crash proof but it uses more computer power than Safari or Firefox. It supports swipes and zoom gestures but not as smoothly as Safari. I like that swipe back loads the page almost instantly without the refresh pause Safari exhibits. The WebGL Aquarium struggled and took CPU temp up to 105c within minutes and the fan ran full speed until I went to another page, but cooled right off. Running Activity Monitor, you can actually see Chrome use and release RAM as you move from page to page, so it's probably the most memory efficient of the three.
Safari has been consistently the most solid in my experience. There are a few rendering issues I've run across but nothing that totally disables a page or makes it unreadable. I've turned on WebGL and have had no issues, running the Aquarium at 60fps, CPU steady at 95c for an hour. The only thing I really hate is the page reload when going back, and I have a habit of hovering my fingers on the trackpad and the forward/back swipe is pretty sensitive so I accidentally flip back a page.