I use a pre-chiller from spring to fall. Ground water in N. Texas can be as warm as 80 degrees in the middle of summer. Pre-chillers are not ideal IMO due to the added cost of the ice. Luckily I have access to 20lb bags for $2, but that is still and additional $2 per batch. I treat the prechiller with rock salt as well to help lower the freeze point.
I only chill until I use up about 45 gallons of chill water, normally this gets me to around the mid 80's. From there I rack to my fermenter and let the ferm freezer take it to pitching temp.
Gently stirring while chilling is a big help.