I have been using the free version for a few weeks to see how it works, and have had no real problems. I like how the program will pull in current weather, and uses whatever measurement (km, miles). This makes it easy to compare distances and times.
There are a few glitches when saving runs (the keyboard wont go away), but overall very happy. Upgraded and will see if there are any differences.
Stephen_C about Run Speeds - Track and log your workouts, v2.4