I\'ve been using it on my sl5500 for a while. Heres the relative speed tests:
1) Handwriting recognition: barely 5 - 7 words a minute, due to recognition inacuracies
2) On-screen keyboard: about 15 - 20 words a minute
3) Quickscript: Just achieved 20 words a minute, and still improving
4) Hardware keyboard: 30 - 35 words a minute
5) Normal computer keyboard: 85 - 100 words a minute.
The best way to learn quick script is to take a standard typing phrase, such as \"The quick brown fox jumps over the lazy yellow dog\", and input it a few times. Don\'t push yourself too hard at first. Once you get the general feel of it, common words (such as \"the\") will end up becoming a single gesture. Then enter that phrase maybe a dozen times a day or so, and after a couple of weeks you will end up with pretty good proficiency. Then start using it in you normal everyday usage.
Highly recomended, more acurate than regular handwriting recognition, and much easier on the hands.