Difference b/w commercial and consumer plasmas

I'm looking for a 42" (possibly 50") plasma, and what striked me, is the price difference b/w commercial and "consumer" units. For instance Pioneer 433 CMX sells for $3,725 (commercial), and the same size non-commercial is almoct 50% more expensive. Is there a difference in audio inputs/outputs?, and if there is, can the commercial one be used in HT application (surround sound), or not.And please, somebody explain the principal difference/differences: (tuner/no-tuner, etc).
What are your suggestions on the best plasmas?
So far I've been looking at Hitachi, Panasonic, Sony, Pioneer.
Also (hope it's not too much to ask)- what's more important for subjective viewing- the resolution, or the contrast ratio?
Primarily it is the the amount of RF releasec between the the comercial versus the the consumer verison.Also the digital artifact motion chips usualy are not in place in the commercial version,and the finish is not as nice.
Also Commercial and some consumer versions have loud fans up to 50db... so check that out.. the gateway is really loud and is pushed too hard. If you can get the higher resolution 1024x768 then you are ready for HDTV otherwise the lower is perfect for DVD 480p. Panasonic is one of the best rated when I was looking. If you don't get a tuner version hook up you old VCR (it probably has a better tuner too), also remember to check the price of the accessories like the wall mount.