I'm sure that every device holder has drawbacks but I honestly feel that this is one of the best choices. Of course, aside for using it for navigating the roads, I really don't recommend you use your phone while driving - it's just too risky!
Pros: This has an advantage over all the ones that fit into the vent louvers or a cup holder - it doesn't take up that useful space! You can position it where you feel is best on the top of the dashboard because the base has a thin layer of very sticky rubber that will probably stick even if you don't clean your dashboard first (but I suggest that you do not tempt fate). The rubber is washable, too! Because of that rubber, you can probably safely place it at an angle, although I have to wonder how it'll perform in 100F degree temperatures when almost vertically placed. It's dropped into the 20s (F) here but there've been no problems so far. It has a footprint of less than 5"x5" and it's easy to move to a different position since there are no mechanisms holding it in place. Since it holds your device in place instead of it resting on a flat surface like a flat non-slip pad, your device is less likely to be seriously damaged during a collision, I think. And, since it has no mechanisms or electronics, the chances of the Wifort ever breaking are slim, meaning it will outlast most of the other device holders on the market!
Con: When you take it out of the box, there is a thin plastic sheet covering the sticky rubber foot and there are no instructions to explain that, so I actually almost pulled the rubber foot off trying to get the sheet off. This is the only "installation" issue. ;)
Pros: There are protrusions in front of each end of the back support, each of which is covered with silicone rubber, that keep the phone in the "channel" without damage and doesn't allow for sliding, wobbling, flopping and slipping unless your phone is too thin for it (for most mobiles phones and GPSs between 0.24-0.47 inches thick). There is almost no occlusion of the screen unless you have a very long device.
Con: It's designed to hold your phone in the horizontal position, so any apps that only work in portrait mode will be sideways. On my Android phone, at least, that includes the "desktop". I'm not sure if that's a flaw in Android or if it has to do with my background picture.
Pro: There are two slots that you can use to direct your USB cable out of the way between it and the charger, so the cable doesn't interfere with controls, especially the turn signal/wiper/lights stick and the gearshift. I find that to be a great safety feature, even if it wasn't intentionally designed for that purpose!
Con(ish): If you want your phone to be upright instead of horizontal, you'll need to wedge it between the back support and one of the protrusions but, if your charging port is on the bottom, you won't be able to charge it. If there's too much of a slant to your windshield and depending on the dash, you may not be able to put it upright.
Pro: Since horizontal produces a smaller visual barrier for driving, it is preferable.
Con: One oversight of this model is that there was no consideration made to make sure that sound from the rear-facing loudspeaker will be captured and bounced back to the user, which can make it hard to carry on a hands-free call unless you also have a bluetooth speaker to send the audio to.
Pro: In front of the slot for your device, there is a shallow tray covered with ribbed silicone rubber that you can use for small items that might otherwise slip and slide.
One other thing that is a problem with some apps rather than the Wifort is that some apps display ads and that takes up too much display space in landscape mode, making it pretty hard to see enough.