Really depends on your goals. The whizzer cone extends the on-axis frequency, but the radiation pattern still narrows. I personally dislike how much the imaging changes with slight head motion, while others may praise the "pinpoint accuracy". Well implemented coaxial drivers have a fairly consistent radiation pattern, and enough width to accommodate 2-3 seats.
Full range drivers still need a crossover, most have a rising response, and audible breakup modes. A bit of baffle step compensation + 1-2 notch filters is usually required for a good end result. Speaking of which, looking at that Seas driver, it isn't 94dB efficiency. Looking at the mid-bass region, it is more like 87-88dB. They only say 94dB because the treble region is 95+, so they do a bit of deceitful averaging.