I was forced to use their shitty desktop version inside a Windows VM because I don't have any Windows or Mac machines, and the web version doesn't support married filing federal jointly and state separately.

Their desktop version seems like a webapp embedded inside browser frame; I don't understand why they can't make it available on the web.

Same for domestic partners. They push you into their desktop version for some reason, but the desktop version is a buggy pile of trash. I wasn't able to use it at all even on a windows machine. To their credit, they did refund the software without too much of a hassle (I expected a giant fight).