Boy, there's lots of buzz about the iTrip. I read some of the reviews, and a lot of it sounded like Griffin PR in disguise! I am not an audio expert, but here's my two cents:

How I got it:
I ordered my first iPod (20g $299) from MacWarehouse along with an iTrip on Saturday. I always buy stuff from my local independent Mac shop, but this deal was hard to find. I recieved the all-to-familiar message from the retailer that the iTrip was back ordered for at least a couple of weeks. My iPod arrived Monday, and to my surprise, the iTrip arrived today (Wednesday)! Guess I got lucky.

What do I have to compare it to?
IROCK transmitter: in my opinion, this is #3 out of 3. Reception is limited to four channels and is very sensitive to placement. You have to get it in a sweet spot - and because there is no mounting hardware or anything like that, it slides around on that leash like a little excited terrier. Batterys flow in and out of that thing like people coming in and out of a liquor store. I used 4 batteries on a 7 hour car trip. I feel like laying it on the ground outside and hoping someone picks it up.

TRANSPOD: I picked up one of these when I found out the iTrip was on back order. I plan on taking it back. It has a really useful bracket and works as a charger and looks very cool (especially with the back light on at night) from inside and outside of the car. The tuner allows for more tinkering, but it still put out a lot of hiss and white noise. Of course - it is a small FM transmitter - what was I to expect? For the price, I suppose I expected more power - especially since it is powered from the cigarette lighter. Better than the iRock, but not as good as the...

iTRIP: For an fm transmitter, the much-talked-about iTrip does deliver nicely. What a difference from the other two! Let me say this about presentation (and most of us Mac people really appreciate this): is Johnathan Ives moonlighting for Griffin?! Packaging, simplicity, seamless software and hardware integration - these qualities make iTrip look and work like an Mac accessory should. As for performance: the iTrip is the best choice if you don't want wires or if you don't want to put an FM modulator behind your deck. I have a lovely old Volvo 240 ("brick"), and I didn't want to mess with the factory stereo/cassette, and I'm too lazy and cheap to take it to some big-box electronics store and watch some kid tear apart my car. For those in my situation, th iTrip sounds like a good tape playing in your tape deck - not like MP3s, CDs, or even the best format for high fidelty, vinyl play at home. It sounds like a low-powered radio station - which it is, sort of. My regular radio stations usually sound better, but in some locations, the iTrip sounds as strong as a clear radio station. Keep in mind, I live in Southern California and the radio spectrum is chalk-full of corporate radio (even more so since the FCC crapped all over any last vestige of the public interest with its deregulatory policy on Monday). I plan a road trip on Friday, and look for wide-open air-waves. For easy-to-use FM transmitters, this is the best. It will not be as good as an FM modulator or as a direct line.

PLACEMENT:
My 20g came with the boring Apple carrying case. It has a nice clip that conveniently snaps on my dash tray. Mounting is no problem in my 240 (it looks sort of cool with the iTrip's LED light on), and might clip on to lots of places in other cars.

-Pancho Urbano