I have used the similar product designed for in the house for a couple of years, and it works fine.  This one does, too.  The install is mostly a matter of routing the cable so you can install the little external antenna, which has a strong, magnetic base.  As others have done, I mounted it in the back of my Expedition near the rear window, and it seems to work fine.  I glued a metal washer to a flat spot on the passenger side near the back window and stuck the antenna to that.  The holder for the phone goes near the driver.  To use this, you put your phone in the holder.  It only works when the phone is in the holder, which is fine, and I got two bars increase (I live in a pretty remote part of Arizona).  Simple to use -- just put the phone in the holder and put it on speaker.  If your phone works through your radio, that would be great.  I took off one star because the adjustable arms which hold the phone don't expand far enough to fit my Galaxy S III with the Otterbox case on it.  Other than that, It's great!  My wife has the same phone with a thinner case, and hers fits fine.