Editsaurus

You enter your text on the left (all formatting is removed) and it shows a copy with highlights on the right. Here's what I found:

Pros

• What I loved about this was that it found filler words you can often remove.
• I also think it's brilliant to have a pronoun highlighter, so you can check that it's clear who the pronoun is for.
• It does a great job of highlighting the usual grammatical pitfalls.
• It highlight doubled words.
• I also like that it has commonly misused or misspelled words and phrases.

Cons

• I wish it had readability scores for each sentence.
• I also wish it could handle formatted text.

Bonus: It has explanations of what it is checking for and links so you can learn what it each category of highlights mean.