Ranked in these QuestionsQuestion Ranking
Pro Font proportion is perfect
Width is just right (not too narrow not too wide). Many other fonts lack this.
Pro Smooth with antialiasing
Smooth at small sizes while still clear.
Pro Readable at small sizes
All characters are easy to recognize at small sizes (comma, period, etc).
Pro Easy to read
This is subjective but this font is very easy to read. The letters are all spaced and sized properly.
Con "mp" clump together with smaller sizes
E.g. in "The quick brown fox jumps over the lazy dog"