I suggest staying mainstream: Yakima and Thule both have attachments specific to your load, and lots of others for whatever sport you may take up in the future. They'll last forever with minimal care and maintenance.
As an added bonus, you can usually find common components like rails and boat racks on Craigslist and save some money.
Whatever you choose to do, don't go cheap. In my experience, car racks are 100% you get what you pay for.