JEFFREY J. EARLY  The issue commented on by BRETT4 was a result of bad firmware in the Canon 40D outputting invalid CR2 files and has long since been resolved. The camera's firmware update fixes the issue, but also GPSPhotoLinker works around the problem. See the Version 7.05 release notes of ExifTool, http://www.sno.phy.queensu.ca/~phil/exiftool/history.html  
(Version 1.6)

BRETT4  Turned my Canon's CR2 files yellow or green. BRILLIANT! Good thing I had a backup...  
(Version 1.6b5)

ANNDRA  Annoyingly, would not add the GPS info to my Photos! Everything else was perfect. Darn!  
(Version 1.6)

BLUEPOLO  This is a great application for adding GPS data to your EXIF data. You can't beat free! Occasional stability issues.

If it had the jhead style ability to save the adjusted file with the original date/time I'd give it 5 stars.  
(Version 1.6)

CYBERBRENT  I will try this out, but also am going to go with what the photo guys on TWIP Podcast http://twipphoto.com/ have said is brilliant http://www.semsons.com/amaggpsdalos.html  
(Version 1.6b9)

HANGON  raw support missing...too bad...hope it will change  
(Version 1.3)

KAVEMAN  Very very cool program. It takes the time off you data track from you gps and uses that to match up with the time from the picture so you just load the pictures and the .gpx file and you're crusin.  
(Version 1.3)

EDUO  This application is excellent. Does what it should do and does it quick.

If it only could be automated (either automator actions, applescript or called from the command line) it would be perfect, as I usually transfer my GPS tracks and then transfer my photos and the process is always the same for them.

If this was added to the application I'd be completely happy with it.  
(Version 1.3)

POOP1  This app does exactly what it is supposed to do and it's really easy to use. I came back from a vacation and I had all my photos easily tagged in a matter of seconds.

I only have few suggestions:

1) support for more gps types. I have a garmin forerunner 301 and I had to use loadmytracks to download the waypoints.

2) I wish it could support google maps (or a custom URL) in the "view on map" since the server used to load the map only supports US (it seems).

It is a great product and it's far better than others on both Mac and PC.   
(Version 1.3)

ANONYMOUS  This program does all it says it does and very well.

Since the GPS data isn't usually recorded precisely when you took your photo, GPSPhotoLinker offers an excellent combination of choices to locate the photos in time and space. Many other options.

The developer is responsive. I've been writing him for maybe six months with requests and he's implemented many of them. I'm just a satified customer.  
(Version 1.3)