The AC60 has feedback control that you can adjust. Just find the offending frequency and cut them out. That being said, with a T5, keep your body between your guitar and your amp. That solves many problems. You can also use foam in the f-hole inserts to reduce feedback.
I have been playing the T5s since they hit the market and have never had a feedback issue. You may want to cut your highs a bit if that is where it is coming from. Some venues will haunt you with a certain resonant feedback like a low-mid squeal, but I have not had any problems with the T5. I often use the Roland AC90 and no issues.
If you have anything else in your signal chain that could be a problem. Make sure you don't have gain staging issues, (where you have preamps raising your gain too high into either the next input source or your amp, resulting in higher noise and more susceptible feedback).
Good luck!
davidc