I use SpringPad for a LOT of stuff and find their Chrome app and extension to be great. I do agree that the editor for notes could be improved (font choice, ability to highlight text, change text color, etc.) I know the engine supports displaying that stuff because if you copy-and-paste into a SpringPad note it will display different fonts and colors just fine but then you can’t really make any edits to those things. HTTPS support would be nice, but I don’t really ever use public WiFi so that’s not a huge deal to me (and I don’t keep passwords in SpringPad!)
My biggest use for SpringPad is as a planning tool for my blog. I have a gaming blog about Diablo II & III and I use SpringPad to plan new videos I want to make, and if I’m planning a new article it begins life as a note in SpringPad which then gets subnotes as I pull everything together that I need to write the article.
Overall I really like SpringPad and am looking forward to any improvements they send our way.