Unless I was in the mood for generally riskier driving safety or at a track where I was TRYING to hustle an HCG vehicle around for pure performance, I'd LEAVE the ESC on all the time (as I do). Even in the dry, you may come upon a two wheels on - two wheels off circumstance or maneuver (say on a sandy shoulder or freshly sprinkled leaves not raked up for Fall just yet - both examples I have come across) that you didn't/wouldn't expect when you turned the ESC off - and it could be an elbows & a$$ situation later regretted IMHO. But yatta hey, it IS your car ...Thanks everyone for the welcome.
On the note of faster acceleration response. Is there a huge disadvantage to turning off ESC or even just setting it to Offroad for general dry weather driving?