the 800 watt SS draws about 620 watts in bloom (450 in veg). I have the 400 watt SS and it does get hot about 84 with fan on. Not nearly as hot as my 400 HPS, so savings are that's its much easier to keep cool in a tight space.
I have the 400 watt Solar Storm, which you can get for a lot cheaper if you go through the Grower Feedback Program. I think they also may be offering a small discount on the 800 watt. I will be posting my initial thoughts of it soon.