This is shout-out to a service that has done a superb job with cross-platform compatibility year after year. It is where I have filed my taxes since I began using Linux on a regular basis. That site is TaxAct.com.
TaxAct is the only one I have found that works flawlessly in Linux. They support Chrome, Firefox and Opera browsers (my top 3) and I have been exceedingly happy with the service.
As of this post I have just completed my taxes...on the original Gigastrand Laptop...in Chrome.