I don't know, there must be a reason why people use them in 1/12 over NiMH.
A NiMH pack cannot provide the same amount of current that a LiPo can, and so the pack's voltage drop under load will be greater. Therefore, I'd say the LiPo would have more punch out of corners, and would be able to sustain that punch for far longer than the NiMH pack.
It will also be lighter - so you'll be able to gear up slightly (as with the extra punch) which balances the less voltage than a 4-cell NiMh pack problem.
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