FahMon was an old favourite, but when early return bonus was introduced with the A3 units a lot of people moved away from it as they were slow to update the app. Just checked on their site and they claimed they have added support since late last year. You can try that out.
While FahMon was not doing its job with the A3 units, another guy stepped up and wrote the HFM.net app, which is now gaining traction since it is the first one to feature the early bonus ppd calculation. This is the one I am using now.
Assuming FahMon is now working with the early bonus, I would say either one of them will be good. Try them out and choose what you like. You can also compared them side-by-side with your points page on Stanford/EOC to see which one seems more accurate for you.
Edit: looks like the long-forgotten FahSpy has been updated as well. Add this to the ring too.
Edit2: this thread
contains a lot more than I can count.
The Model M is not for the faint of heart. You either like them or hate them.
Gerbils unite! Fold for UnitedGerbilNation, team 2630.