There are lots of options for sissy bars. Yamaha even makes an OEM one with two height variations.
Just because it is the OEM version does not make it the best. Many have had issues with the top half of the sissy bar breaking at the bolted mounting points on the lower brackets. Usually this occurs when someone uses the bar to push or maneuver the bike or when the bar gets put under load somehow.
The best option for a good sissy bar is truthfully a good fabricator and the price is generally fairly comparable to the OEM.
Knock-off Amazon/eBay Versions #
There are version of the OEM one on other sites but they typically have the same issues and more as the OEM one.