slightly better results mate,cheaper than buying good soil every time,but a lot more easy to fuck things up...on my first grow in hydro i had 2 in hydro and one in soil as a back up.How you finding Hydro? I kind of never want to leave soil lol.
You should let your water stand out to warm up to room temperature. You can always add a small aquarium heater to raise it before changing your reservoir. You don't want to shock the roots anything below 60 F is not great for the roots and shock could set in