Working here, I have had some influence over the department that does MobileSSH development, which added a lot of very useful features that make it the best MobileSSH software.
It has shortcuts for easily transmitting CTRL and ALT keys, and the splitscreen makes it very friendly on high-lag networks (most carrier wireless networks are laggy), as well as the new ability to multitask multiple
concurrent telnet/ssh connections, and other useful features
The free trial of Idokorro MobileSSH with ssh/telnet/3270/5250 is at: http://www.idokorro.com/imssh.html
You can try out other competing software such as midpssh and compare the software -- and see what works best -- a lot of corporations prefer MobileSSH.