Hey qball114, I'll try to answer this one best I can.
SoftMod is basically iSRObot, which, im sure, you know well enough by now.
T-Bot grinds much faster than iSRObot, has a little different features and isn't as refined as iSRObot. Though, bot258 has, I think, done a marvelous job in creating something to call their own & incorporating new features such as the hud display, that, even if wasn't used much, is refreshing. The only downside is that it still dc's more than iSRO, and it's usage is more easily recognized as a bot if you're the one getting ks'ed. It doesn't have the delay that iSRObot has after you kill a mob. T-Bot targets rather proficiently, and that has definitely been a plus in the customer's eyes. Further more, bot258's selling practices for time botting are different than their counter-part. They charge $5.00/week or $16.00/month instead of using credits. For the 24/7 botter this is definitely more advantageous.
Now, as far as security goes I know that iSRObot passes "gameguard". However, I'm not sure on the earlier versions with T-Bot that gameguard was bypassed. Though, lately I've noticed with 530 and 531 that I havn't seen the gameguard load up.
Basically I believe they're both safe...lol its gameguard.