The biggest argument of the whole thing is quality over time. What ones are going to sound awesome, and for approximately how long? That's the biggest question, and a lot of companies depend on us to ask ourselves that very question. We tend to believe that a $600 speaker will sound as great as a $900 speaker, but psychologically we convince ourselves that the extra $300 will give us a lot more time with that awesome sound.
good speakers should last till, well, last till youre tired of them. 10 years easy, more like 15 - 20 years. just dont clip the amp too much. a clip every few minutes for an instant is OK, but when its at clip for 10 seconds at a time, your speakers will die, no matter how good they are. a underpowered amp run routinely at clip can kill a speaker way faster than a overpowered amp that is technically over-driving the speaker.
200 watt amp, 120 watt speakers, no clipping, clean source = good, the speakers will take it as long as youre not totally crazy.
120 watt amp 200 watt speakers, lots of clipping = burnt voice coil. toast.
I havent blown a driver in like 20 years. I wind up giving the speakers away.