I have a Shark Navigator Vacuum and use it on my hardwood floors all the time to get them clean.
The shark navigator I have is the Shark Navigator Lift away vacuum and has a hard floor attachment that is made for cleaning hard floors without scratching or harming them.
I bought my Shark Navigator Lift Away Vacuum cleaner from Walmart for $160.00 and it's been well worth the cost as it does a wonderful job cleaning my hard floors and even carpet around the house
It's a very powerful vacuum as well and would recommend the Shark Navigator Lift away vacuum cleaner to anyone needing a good vacuum especially for hardwood floors.