One minor downside to the Snap 2's magnetic design is that because a gentle tug is necessary to remove the phone from the mount each time, the Snap 2's blade does eventually work loose from the CD slot — every few days I had to give the mount a gentle push to seat the blade firmly into the slot. I suppose I could have tightened the blade more, but I didn't want to apply too much force to the CD player's slot. Still, this is a minor issue — in my experience, I had to reseat the Snap 2 much less frequently than the constant fiddling required with many vent-attached mounts.
Overall, the biggest limitation of both Mountek mounts is that if other controls or displays are directly below or above the CD slot (or whatever horizontal dash opening you use as the mount point), the nGroove or your phone may block access to those items. For example, our car stereo's large volume knob is just below the CD-player slot, so the Mountek mount makes it more difficult to turn that knob. (For me, this inconvenience is easily overcome by the volume buttons on the steering wheel.)
But if your car's dash accommodates the nGroove mounts, I highly recommend them. They're cleverly designed, sturdy, and convenient. I personally prefer the Snap 2 for its more-compact and -elegant design, but you can't go wrong with either model.
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