The gearshift indicators are a suggestion to change up or down to help with fuel economy.
The hill assist only kicks in on a certain incline when you have your foot on the brake - if you use the handbrake the assist doesnt come on.
You have to becarfull when accelating the first few times until you get used to the "hold" as you can give it to many beans and you look a bit of a twit as the car shoots off up the hill.
Personally I like it, I don't always use the brake to hold the car, still use the handbrake if i know the lights are going to be red for a while, but if its a short stop then it's nice.