Very poor quality Rated 2 out of 5 stars
As others are saying, this is a very poor spell checking dictionary. Tons of common usage words missing. Spell-check dictionaries are NOT the same as English dictionaries and should contain all commonly used words, people's names, common place names, such as UK towns, computer (or indeed any common) terminology and jargon, abbreviations etc, etc. Just compare with commercial quality dictionaries such as those from Microsoft, and you'll see this simply does not compete.
And for users in the UK to NOT have this installed as standard is ridiculous and not competitive with other browsers.