Go check the EE, Rooftop sells New PLHv2s for less than that site wants for that 600DF (300$ is crazy!), and others frequently post their used ones up for less as well. The PLHv2 is incredible. You will NOT be disappointed in it. If you are worried about batteries, just buy a few spare 18650s and a good charger. Modlite requires a specific battery output for their lights to function at full strength — you need a minimum of 10 amps, but 14 or more is best. I bought some Acebeam IMR 20a 3.6v 3100mAh Li-Ion batteries off of Battery Junction and they work great in my Modlites.
The 600DF is cool out to, like, 75m, but beyond that you really notice a drop in performance. The PLHv2 is good to at least 200m, and the OKW out well past 400m, but that PLHv2 has much more spill to it, which makes it even better for home defense. Not that the 600DF is bad, or that the OKW wont do the job, but the PLHv2 is heads above both for HD usage.