Works flawlessly with Windows 7 64-bit. I recommend changing the configuration to use AltGr (the right alt key) as the compose key. This is similar to european keyboards. You can then input characters such as ñ by entering <AltGr> + <~> + <n> or é by inputting <AltGr> + <'> + <e>. The AltGr key becomes a meta shift key that toggles deadkey behavior of other keys to enable combinations to produce diacritical marks, accent characters, and more.
Unlike the old (non-Unicode) AllChars, this software isn't really usable anymore, alas. There are a number of serious issues (Control characters don't work, dead keys don't work, AltGr-generated accents don't work) and there doesn't seem to occur any bug fixing anymore.
There are no 4 star reviews.