In smart mode, the drone moves in relation to you, not necessarily in relation to the way the drone is pointing. In other words, when you tell it to go left, it goes to *your* left, even if the front of the drone is pointing off at an angle. This makes it really easy for a new operator to pick up and immediately get use out of the drone. I've handed my controller to six or seven people, without any training or explanation, and they've all been able to fly it right off the bat.
Smart mode is also "follow me" mode, where you can move with the controller and the drone will automatically follow you. This is meant for people skateboard, biking, or otherwise doing something with movement they want to capture. I haven't been brave enough to take it on more than a brisk walk, but it did follow me exactly as advertised.
Once you get more experienced, you can flip it into "angle" mode, where it flies according to the front of the drone like other drones. You can also start out in smart mode to get the drone where you want it in the air, and then switch to angle mode and use the live video feed to fly according to the camera. The drone also has a "return home" option, so if you've lost sight of it you can flip the switch and it will immediately fly to within a few feet of you and land. You can also flip it back into one of the other flight modes once you have it back near you. (Never fly a drone where you can't see it though.)
This drone is a great deal. For the same price as most other drones, it comes with a second drone battery, case, and has live video display screen built directly into the controller. The controller and screen use the same battery, so there's only one device to charge outside of the drone batteries. Other drones require you to provide a smartphone or other tablet for the controller, which can add a lot to the cost, and is another item to have to carry, keep charged, and monitor the battery life for.
The included 4K camera is wide-angle, but specifically designed to almost completely reduce the fish-eye effect you get on other drones, particularly drones that use a GoPro to record. It's also one less item you have to purchase, charge, and monitor separately. I don't have a 4K TV yet, so I set the camera to 1080 mode, and the video quality is noticeably superior to even the earlier Typhoon's native 1080 camera. (I'll upload a video example.)
I did run into a problem where I didn't tighten one of the propellers well enough, and it came off when I was in the air, but I never noticed until I landed and went to put everything away. It flew with three propellers for at least ten minutes without anything more than a slight wobble, and the camera gimble is so good that you can't even tell on the video when the propeller came off. I used to be nervous about flying it over water, but after that I was a lot more confident about it staying in the air. (I'm also a lot more diligent about tightening the propellers.)
Like other GPS-based drones, this drone positions itself by specific lat/lon. It will pick up at least a dozen GPS satellites, so when you tell it to go to a certain spot in the air, it will park there and stay. You can even push on it, and it will fight against you to stay where it should. I've flown in moderately gusty winds, 5-15 mph, and the drone will sit in the air at an angle against the wind to stay in it's spot. Even then, the camera and gimble makes the video level and rock steady.
The only downside to this drone in comparison to other drones is that the controller video is not high-definition, and the video lags a second or two behind. It's still perfectly fine for flying the drone, and you'll get amazing video recorded on the microSD in the camera, but the the DJI Phantom or Inspire do win out on the quality of their controller video. With all the upsides to the Typhoon in comparison, I can live with a "good enough" controller display. .
Of course drones as a technology are still in their infancy, and in five years all of today's drones will look like old Model-Ts, but if you're looking to spend serious money on a drone right now, this is the one.