I personally prefer being able to have threaded conversations, but the linear forum is fine.
TapaTalk has been a usability flustercluck for me, so I don't use it. SMF doesn't do a responsive design for smaller screens, though, so while I can read on my phone, posting is really difficult. Text in the text box is illegibly tiny. Other text is vastly large.
On my iPad I'd love to be able to resize the text box.
On my Android phone I'd love to have the text box have a responsive width.