Works well. I have it resting on the dash ...
587401
Works well.  I have it resting on the dash so there is minimum vibration.
3923531
I have a 2004 Prius with Factory CD player (the kind that has the velvet in the CD slot). This installed easily enough in that slot. I did not try putting it in any of the other cracks in the dash but it looks too thick to me.
I got this in the slot and tightened the nylon/plastic bolt and popped my iphone and and was very happy with it. It tilts and swivels in every direction by a little (enough for my purposes) and it is easy to tilt yet it stays in place. However, when adjusting it on the 3rd time I used it the mount had worked its way out of the CD slot. I was not pulling on it that hard or anything so I was surprised. I tightened it more but think I am at the limits as some plastic started to strip from the bolt (I think see photos) and the top and bottom halves of the wedge look like they are coming apart a bit.  At this tightness I am sure I could still pull it out but I am not going to try because I feel I may have worn the threads to the point that I will not be able to reset it a 2nd time. Now when I adgust the tilt I push in as I do it just to make sure it won't work its way out.
It has minor wobbles on an average road but I am happy with the stability I just don't have a lot of confidence that I can take it out and put it back often (i.e. if you wanted to use it in different cars or wanted to move it to use the CD player which I never will)). I think I have a pretty standard CD slot so I am a little disappointed that it is not better suited to it.
Also the bottom support snaps off in a way that makes me feel like I am breaking it. It is really shallow and phones in cases won't sit on there so well and in fact it will block the dock connector if the phone were resting on it. Fortunately this is not needed- the side clamps hold the phone very securely. The bottom support is nice for keeping the connector handy but still not necessary.
I do find the button you squeeze to release the phone a bit hard to reach while the phone is in there (and this is another time I have to be careful not to put any outward pressure on the mount that might make it come out of the slot again.) I am kinda short though so maybe it is just me...
I have never tried any of the suction mounts at least not since my first ipod, but I will never trust them to stay on and allow me to interact with a touch screen which this mount does do. SO it has a few flaws but think it is on of the better ones out there in this price range.
1814939
Works well. It's pretty stable and holds the phone firmly. Easy to pop the phone in and out. My only complaint is that it sometimes vibrates and makes a rattling sound when the car idles.
2599549
Works well.  Breaks down flat. Comes with a pouch to store it in!
2938356
Works well in my daughter's car.  Not quite as solid mounting to the dash as she'd like.  Comes off occasionally.
1233207
Does it's job, and does it well.  The little "leg" that rests on the dashboard is a particularly thoughtful feature. It can be slid along the arm and placed wherever it needs to be.  I didn't take off the backing and use the stick-on feature--it sits perfectly without using that, and therefore can be used on another vehicle if the need arises.
3237697
Holds smart phone well on dashes that are level or somewhat close to it.  You can call hands-free (reach over to select person you're calling) or play music or use the GPS features, etc.
Doesn't stick up very high so not too noticeable on a black or dark dashboard (when there's no phone in it).
Very happy!
1432658
Works as it should.  No issues with the functionality.  The 'brick' is a little larger than desired.  Works great for something I leave in place.  I use a smaller power supply for traveling.
2081597
Works well but does move around when driving, so you really need to apply the stick on anchor if you don't want it to move on your dashboard. That's the only negative. I choose not to use the anchor because I don't want things "stuck" to my dashboard. I wished they used a more tacky surface for the bottom of the unit which wouldn't allow it to move and no need for the stick on anchor.
2525804
No fault of this manufacturer, but my car dash has very little flat space so it's hard for me to get the right angle on my phone.  Otherwise, the product works just as described.  No complaint there.
800816
This works very well for it's intended purpose.  It holds the phone securely, and has a latch to keep it from popping out if you hit a bump.  It also has an insert that allows you to use the dock with or without a case on the phone.  It tells the phone that it is connected to the vehicle dock so you can set up smart actions based on this.  It also has an audio connection so you can connect it to the aux input of your stereo.  The suction cup is pretty strong, and has not fallen off yet.  The overall assembly is a little bulky, it takes up more room on the dash than my GPS unit's mount.
3930754
This one works pretty good. Only problem I've had so far is that when I got to higher elevations it popped off the dash. I remounted it and pushed in on the plunger then flipped the lever and I haven't had it happen since. the bottom shelf opens on the left took me a few minutes to figure that out. But since my charger plugs in on the bottom I haven't used it. It grips well enough so I haven't needed it. I have a protective cover on the phone and it still holds the phone with no problem.
345296
The folding feature makes it easy to keep this compact against the dash instead of sticking out and all the ports work as advertised. No issues yet.
1937955
Good for but will pop off the dash even if you lower it so you phone or tablet is resting on the dash.
1504700
Works pretty well with my Prius C 2012 ... though it bounces around a little, sometimes depressing the "setup" button on my head unit. Wish there was a way to keep the legs fixed to a position. That said, it holds the phone well, and I'll try to figure out some kind of "gum" to keep it from bouncing.
342131
This is probably one of the better dash mats I have used or seen. As someone who drives a company truck all day, this mat holds my Ipad in place on my center console so I can use it for directions without it sliding all over the place. I actually leave the Ipad stand stuck to the mat and I can raise the lid of the center console to a 90 degree angle without the Ipad stand moving. This works as advertised and is fairly cheep.
818937
Great, no sticky stuff to place on my dash.  I have a slopped dash and this never shifted during my road trips and held my GPS in place.  I also use it to hold my sat radio , again easy to use, when parking I can toss everything in the glovebox or in the console between seats.