The operational scheme is better at reaching the limiting voltages and is more linear, but its response is much slower for high frequencies.
The scheme with two transistors can amplify without problems frequencies of 1MHz or more, which would be very difficult to achieve with the operational.
It depends on the op-amp and the slew rate.
What we have here is a type of
current feedback amplifier, as I hinted in my
previous post. The speed is limited by the turn-off time of Q3, so one can expect it to have a fast rise time and slow fall time. It has a wide bandwidth for low amplitude signals, but will suffer from slew rate distortion, with large amplitude, high frequency signals.
Pulling Q3's base up via a current source and reducing the resistor values will speed the circuit up, at the cost of more parts, higher power consumption and a lower input impedance.
A real current feedback operational amplifier has a push-pull output and the transistors are pulled up by current sources, giving a fast slew rate for negative, as well as positive output swing.
I've done an AC analysis. There's a peak around 10MHz, which indicates some resonance/oscillation.
3V to 12V discrete AC.asc (1.59 kB - downloaded 4 times.)
The transient analysis shows a bit of over/undershoot. Note the fast rise time and sluggish fall time.
3V to 12V discrete tran.asc (1.51 kB - downloaded 2 times.)