When comparing two weapons with different attack speeds, there is no operator (+/-) shown against the value, which may not seem like a real problem due to the colour, but then again as many as 5% of the people playing the game may have some degree of red/green colour-blindness
Realistically though, the names/suffixes of the items involved usually indicate which one will be faster, but not always (as with artifacts), so for that reason and for consistency it makes sense to display the operator.