Well, it's all about time available. If you're too low to start with the chute is just about useless - I'm not talking about opening times just thinking/jumping time.
Personally I hope that it will just be the most expensive cushion money can buy; I keep it regularly repacked and preflight it too but I see the main scenarios in order of likelihood for use as:
1. Structural failure
2. Midair Collision (for formation)
3. Fire in the cockpit
4. Unrecoverable flight regime
5. An alternative to ditching
One has to consider the aircraft type very carefully before choosing the chute (in terms of max opening speeds).
Ultimately, I will not do aeros without one in an aircraft that I stand a reasonable chance of extracting myself from. It is also a must to rehearse the act of getting out in a hurry (bloomin' difficult in some machines!)