If the forum supports it, tapatalk would be great - unfortunately people don't see the benefits of Tapatalk and the idea never gets pursued.
Tapatalk is a much easier way of navigating the forums on mobile devices, and the server plugin is free so I can't see any downsides.
If the forum backend doesn't support it though, a mobile theme would be a good alternative (based on browser user agent - if you're on a phone you automatically get the mobile theme.
Mobile touchscreen devices are rapidly taking over as the main way people access the Internet and needs considering