NOTE: This review is for the first revision CarFM. The second revision seems to have removed the audio wire and added portrait rotation.
I don't usually do reviews and this probably isn't the best place to post a review that people will actually be able to find, but here goes.
I decided it was time to buy a charger, stand and fm transmitter for my iPhone. Previously I had been using the ubiquitous Griffin iTrip FM Transmitter and Car Charger with my 3rd generation iPod, but the old version I had didn't work with my iPhone so I basically decided to leave the iPod in the car. However, I recent decided I needed a stand for my iPhone to better use the maps and GPS while driving. Also, I don't have an auxiliary input on my car stereo. I'd prefer that over an FM transmitter any day.
So I researched a few of the FM Transmitters and stands that work with the iPhone and found none of them perfect, and most of them expensive. I finally settled on a CarFM by pdo because the price was right ($25-$45 depending where you buy) and the reviews were decent.
This is what I've discovered:
1) The CarFM has a headphone wire as well as an apple jack. This allows you to control the transmitter's input volume, but otherwise isn't very useful and requires plugging in two things instead of one. Also your volume will probably be maxed for the car, which means when you later use your iPhone with headphones the volume will be at max, beware!
2) The FM transmitter has a superior signal to any I've used before.
This has partially to do with the fact that it's connected by metal to your dashboard and partially just because it has a strong signal. However, it is so strong that nearby stations gain static. For instance set to 106.1 the transmitter makes the normally clear KROQ on 106.7 unlistenable.
3) The transmitter is always transmitting when plugged into the cigarette lighter, even if no iPhone/iPod is plugged in. I wish there were an off button to save my car battery a bit of charge. I think it's also still transmitting when the car is off, at least all the lights stay on, at least until the car cuts power to the cigarette lighter.
4) Receiving a phone call stops the music and puts the phone on speaker (iPhone speaker, not car speakers). This is essentially useless in a running car. I haven't tried it with a bluetooth headset yet, that might work better.
5) The stand seems to be sturdy enough in my car, better than I thought it would be, but it's still only held up by a circular connector, which might slip more over time.
6) The stand's flexible wire is obviously fixed length. In my case the length is pretty good, better than the short competitors.
7) The auto-seek button works pretty well at finding an empty station, but the transmitter is pretty strong so it doesn't have to be perfect anyway.
8) The station is on the top of the display which is a little awkward, but really if the signal is good you don't really need to look at after the initial setting. I'd recommend making a radio bookmark for the station you pick.
9) The station light and blue indicator light on the charger are always lit, which may annoy you and sucks a tiny amount of power. Not a big problem compared to the transmitter always transmitting.
If that sounds sufficient to you then go for it. It does what it says it does, but it's not perfect.