Good question and here's my .02. I bought my Phantom after flying smaller quads like the WLtoys 959 with a camera for a year. I bought the Phantom 2 without a gimbal believing that I could rig a camera, and that the stability of the Phantom was enough to get good video. I regret not waiting another pay period and getting the all in one gimbal package instead. I did rig several cameras after spending time researching various mounts and have taken some great photos and video. If you just want to capture the scene from the sky and don't mind some shaking, you can go w/o the gimbal. Still photos are no problem either way, though without the gimbal, you'll get a lot of shots at various pitch and banking angles. In my case, I finally got a gimbal, and after much time a research at how to power and mount it properly, I'm hooked on using it. The shots are so much more rewarding, and if I'm trying to capture a specific scene or subject, I can just concentrate on getting the shot, and not focus on keeping the Phantom still all the time. Phantom's are very stable to fly, but unless there is no wind, they will not remain in one place or steady for precise photography. There's flying skill involved, but a lot of luck too that the conditions are right.
I've gotten pretty good at getting steady video without the gimbal (currently out of service). They keys include the following: Fly level. Fly directly forward or backward over your subject. Turn off the GPS if you can, as it's constantly auto-correcting and you get sudden shakes and jerks on the video. If you're in safe range, get off the sticks and let the breeze take the phantom for a short smooth ride. I also take a lot of shots when I simply take the Phantom directly vertical which can make a very smooth shot. Also, if you mount your camera facing straight down, the shaking is less obvious and it's a very cool effect, especially flying low over landscapes or water. Good luck!