This Beta-8 version of the Flex-8 stands apart from the others as the woofer has much higher efficiency (~91dB / 2.83v or 1W/1M).  This high efficiency however comes at the expense of bass extension (F3 ~72Hz 4pi) so subwoofers would be required for most content unless you don't need much bass like basic background music / radio.  

Along with the high efficiency comes higher power handling then the other woofers, this results in much higher maximum SPL from the design.  It also means lower compression, as measured there is only about 0.5dB on average from the woofer at the 105dB sweep compared to 75dB which considering that's 1000x the power level is not bad at all. 

Frequency response from the Beta-8 is also very good, a nice even response without any large issues.  This makes the tonality excellent with good detail and smoothness, things sound like they should. 

Harmonic distortion performance is the only weakness of this woofer, while not bad at lower levels it ramps up more then the others at high levels.  Not sure why it suffers more as power though the driver is far lower then the other designs at equal SPL.  I didn't notice anything bad during normal playback as the levels still stay low enough that they remain masked by general content.  

The high frequency performance/sound quality is largely the same in all the designs so this section will likely be a cut/paste for each.  The LaVoce DF10.101LS with the Celestion H1SC-8050 is a very nice combo, the smooth easy to work with  frequency response  results a very clean clear uncolored high frequencies with remarkably low distortion and compression.  The high frequency driver has to work very little in this design so its composure is maintained well beyond the point where the 8" woofers are begging for mercy.  The only things to point out are the slightly more narrow coverage of the horn then most designs and the drop in high frequency output past 16kHz.  For the cost I don't mind as they are not glaring issues that you notice immediately if you notice them at all and the narrow dispersion can actually be a benefit depending on the desired use of the speakers or the type of sound you like.