Rated 4 out of 5 stars
This is great to get into Memento but the current version (0.7.6) has some annoying usability problems:
1. the slider, target, and actual interface should not be shown at all if memento is deactivated ([m] shown grey)
2. the target and actual date most times show 0000-00-00 which does not make sense. Either hide it in this case or show "unknown" but 0000-00-00 is not suitable.
3. The layout of the target and actual date (unreadable on black) is unreadable - just use text or normal input field color. I also wonder why you need do show two fields if the page is always shown for one specific date and you cannot change the actual date anyway. You could replace it with a message instead.: EITHER "most recent page (YYYY-MM-DD)" OR "archived version (YYYY-MM-DD) "
3. The slider sometimes catches focus and does not give it back. One time I needed to restart the browser! The target slider is crap - there are better UIs for selecting a date (list, calendar etc.).