I think "time to tip the scales" in the default male Robin voice 1 sounds super badass. This might be tied to my own personal experience and memory though. Story time:
On my first playthrough I'd been playing on hard and was having trouble with chapter 11 and beating the thief to the treasure chests. Gangrel and his homies charging took me completely off guard. I ended up having Robin just run up and kill the thief out of desperation, and Gangrel completely obliterated him as he was reclassed to a mercenary and had basically no res, failing the chapter. It had been a doomed effort though.
Anyway on the next try I had a better gameplan. I managed to have Cordelia get the thief quickly enough and escape to the left fort while Gangrel was charging. Most of my units weren't very strong and all clustered in the upper central third of the map, having to pull back in hopes of regrouping before Gangrel got there. But there's so many of them and Gangrel's so dangerous that it just seems like eventually one enemy phase my army's going to get devastated. So I pull off a risky gambit. I have sage Lissa paired up with Maribelle move from the right where she'd been fighting the mages to just inside Gangrel's range while everyone else waits above. He takes the bait and her res lets her shrug off his attack without hurting too badly while getting him down to around half HP.
The next turn I move in with Robin and equip his killing edge. Time for the runback, Gangrel. And what does he do but flash white, grin, and shout "TIME TO TIP THE SCALES" for the first time in my entire playthrough, and oneshot that motherfucker. It was literally the most fitting time possible, because that's exactly what happened. He turned the tides of the entire battle that was starting to look real ugly in a single swing. After that the rest of the army could rush in and deal with the weaker enemies, no longer much of a threat without their leader to put units in danger of dying. I'll never forget the serendipity of that line, and as a result I'll always love hearing it.
Default Female Robin sounds so lame when she says it though, it's super dumb. I don't know if one of the other voices gets it right but yeah, it falls really flat with voice 1.