HC4 vs Puma 1 & 2
Having never flown it, I can't say for sure how a Carson blade HC4 would perform directly against Puma 1 or 2. My educated guess, not as good as Puma 2, but better than Puma 1.
However, the HC4 still has only 1 door through which to get on/off - bit of a design flaw for a support helicopter. From what i've seen of it, it's also painfully slow in the cruise/climb.
In summary, Puma Mk2 gives you better range and performance, hot & high,... than a Merlin.
Fact.