KT70 looks to have easier operation than the TRIG unit - 4 knobs, each one changes one element of the squawk code. For a single pilot helicopter that is much easier, though the "push button" approach on my KT76C is even easier.
The downside of the KT7 is the $5.9k price tag, compared with the £1.4k price of the TT31. Difficult to see the justification for the price difference!