I looked at the intended application and compared spec's and features for the K8.2mkii, DXR8mkii, and the 820P Mkii. I'm liking the JBLs. (I have DXR10s).
As is always mentioned, if possible, try to listen to some recorded music through these things.
JBL 308P Mkii
Pro:
No cooling fan noise (QSC and Yamaha have fan cooling) Soft dome tweeter (QSC & Yamah use a compression driver) Freq Resp.: 45 Hz - 20 kHz +/- 3dB, 37 Hz - 24 kHz (-10 dB) Coverage: 120H x 90V, wider and taller than either QSC or Yamaha the noise performance is specified (neither QSC nor Yamaha) the distortion performance is specified (neither QSC nor Yamaha)
Con:
Power: 56 W (LF), 56 W (HF) I saw one review that said it was "overly bright".
You can really tell from the spec's that the JBL is intended as a monitor: low power, freq resp. spec'd at 3 dB, no cooling fan, distortion spec's listed, noise spec's listed.
For me, the question is whether the JBLs have enough power. Or, do you need a couple of 700 Watt speakers for the house?