I understand that you may have had poor performance from short range FM transmitters. Most of them are "toys." However the one I mentioned is truly an exception. One of the advantages of this transmitter is the ability to tune it to any frequency in the FM range (88.30 to 107.70; note that it can be set to 92.2 or 92.25 etc.) This gives you the ability to exactly match the frequency any on your particular radio.
It's not a "toy" nor is it's performance that of a "toy"; nor is it's price tag of $99.
I use one on my PC. It connected to the output of my sound card. I play all of my mp3 music to a full sized stereo Yahama system about 15 feet away from the PC via this transmitter; it works anywhere within my home. I've used it in may cars (new MDX and Prelude) very successfully. By adjusting the broadcast power, I've never had a problem finding a "spot" on the FM dial that's "quiet" enough for this system to work.
If someone is considering using an FM Transmitter, give this one serious consideration. When I first received it, it seemed under powered. I spoke with the designer, Chris Justice, who was very helpful and was very concerned that I was satisifed with it's performance. C Crane has a very generous return policy. If a customer is not happy they will take it back.