Wptouch is great because mobile usage increases every month. Your website needs a working mobile version or visitors will hit the back button. The plugin sends mobile searches to a bland, generic working scrollable theme.
I encountered one small issue: automatic discovery. Sometimes the plugin showed the mobile version when browsing via Google chrome desktop browser. The Pro version may fix this issue so it's something to consider.
If you want to really impress your mobile visitors, then activate a responsive theme that adjusts depending on the browser.
It automatically adjusts its form to the browser. This way, you avoid any stupid discovery errors while maintaining your website design.
[Link removed - please stop posting them]