It all depends what you mean by "best" the Klipsch... I'll include form factor as well.
Per teh spec sheet
ENCLOSURE TYPE Bass-reflex via front-firing CornerPort™
ACTIVE DRIVERS 12" (30.5cm) Cerametallic™ cone, front-firing woofer
AMPLIFIER TYPE BASH® Digital hybrid
AMPLIFIER POWER FTC Rated Power: 350 watts continuous @ <2% THD / Dynamic Power*: 825 watts
-120Hz ± –3dB
MAXIMUM OUTPUT 116dB @ 30Hz 1/8 space, 1m
CONTROLS DCS control and feature set w/ 3 system presets
INPUTS L/R Line-level RCA jacks, L/R High-level speaker binding posts
Focusing on bolded specs, 24Hz -3dB point (aka F3) and 116dB @ 30Hz, but in 1/8 space, i.e. corner loaded. I'll work with an infinite baffle sensitivity, and so predict a 1/2 space SPL. Given that 1/8 is 1/2 cubed (8 = 2 x 2 x 2), and each doubling in free air is worth 6 dB, the 1/2 space equivalent SPL is 104dB@30Hz, 1m
. Klipsch box size comes out about 2.5 cu ft...
BASH 300 with Umax 12. $119 + $158 leaves some money for a box... a 2.5 cu ft sealed box.
30Hz output is 105dB (louder)
F3 is 33Hz (higher) but...
F10 is 19Hz and the Klipsch is also 19Hz
and a sealed box can take more power, and extend deeper.
BASH 300 with Umax 10. $119 + $144 in a 2.5 cu ft ported box
30Hz output is 106dB (louder)
F3 is 18Hz (lower than Klipsch F10)
... and you can tune even lower, trading 30Hz output for greater extension.
Of course, in DIY the biggest savings is your labor, which is where you can't beat the $300 mark... but if labor is free, it's not hard.