1-2. black & decker to hilti. recommended from least to most.
dewalt, makita, bosch goes in between.
3. not advisable for low speed operations like mixing paints.
these drills runs on very high speeds... hard to control for such job.
4. yes!
5. usually runs on 220volts. "wattage" matters. heavy- duty drills have
higher wattages, to do heavier jobs. electricity thirsty thou.
6. yes. 3/8" chuck can handle a 3/8" bit and/or smaller. not a mm bigger.
7. b & d. most i've seen in hardwares. anyway, "proper" charging, will last for years.
ALWAYS READ THE MANUALS BEFORE USING.
happy drilling!