detgnome,
Before I trained as a test pilot I flew SAR in Canada for ten years.
The company's that do offshore and SAR are typically providing SAR for their own aircraft, hence flying in the same weather. Granted, if they are providing SAR for others then there could be a difference in the weather they fly in. What are the limits for offshore pilots compared to SAR? I think you'll be surprised how similiar they are.
As far as the skill set, I've flown the majority of my SAR career in the mountains of BC and off ships in the Pacific Ocean. I stand by my statement. Helicopter pilots need to hover, sometimes its challenging sometimes not, but the skills that you employ are the same regardless of the reason for hovering.
I agree there are differences, but not where you seem to think they lie.