I use it at least once a day, and it's great for boosting your range because you can pre-heat and pre-cool the cabin before unplugging. Heating and cooling take a lot of energy, so doing it from the grid makes life easier on the battery. It can actually improve efficiency if you're in any extreme climates, as it will heat or cool the battery if necessary.
The manual says on page 2-8:
The climate control system will use the previous settings during a remote start. The rear defog may come on during remote start based on cold ambient conditions. The rear defog indicator light does not come on during remote start.
This is slightly misleading, however. It uses the previous settings EXCEPT fan speed. I've got into the habit of leaving the temperature set at something like 74° in the auto setting ("temp" button active) and only adjusting the fan speed for nearly all of my driving. If I'm comfortable, I turn the fan speed to off or the lowest setting. If I'm uncomfortable, I just push the auto setting. That way, even if it is hot or cold outside and no matter what the temperature was when I turned the car off, when I use the "remote start" feature with my key fob or with my iphone app, the car turns the fan on and uses my previous settings otherwise (auto, 74°, "temp" button active).
Of course, for maximum range drives there may be times you need some fan for defrost but push the "temp" button to deactivate the heater/air conditioning for the sake of efficiency. I'm speaking about my habits generally...generally, I leave it on "auto" and just turn the fan speed down until it's off if I'm comfortable.
This is better than my Leaf because I can set any temperature or HVAC setting I want in the Spark EV, and it will do that particular thing when I precondition the cabin. For example, if it's really hot outside and I want the car abnormally cold...I have that capability by setting the temperature to my desired amount and leaving it on auto when I shut down. Unfortunately, the catch is that if your intention was to have a car warmed to 74 and you accidentally forgot to leave the auto setting and "temp" button active at 74°, then you won't get 74°. In that regard, the Leaf is more dummy proof.
Obviously, if you're not plugged in to a Level 2 charger, using this feature will use the battery and reduce your range. Don't use it if you're not plugged in and need all the range you can get!
Funny note...I've noticed that when I'm preconditioning the car, I'm pretty sure my phone is syncing with the bluetooth in car. I haven't tested this theory to see if the radio will actually function this way...I doubt it would, I think it's just a software bug that they accidentally take over my phone even though the radio doesn't intend to do anything with it.
Bryce