If it’s fiction, you can use the trademark name, not the logo, without the registration mark. Writers do so constantly. If it’s nonfiction, you must use the registration mark.
You don’t have to say nice things about a company, you just can’t lie. Ever see the film “Super Size Me”? Talk about saying nasty things about MacDonald’s.
We’re all allowed our opinion, whether it’s good or bad. How many websites can you find that call Wal*Mart evil?
If you think a company or a product bites, you’re perfectly free to say you believe this.
But companies must protect their trademarks, or that trademark will fall into public domain, so you should use the word correctly.