I have one. The air IS heated. It is heated by the air passing over the motors so when you flip it on it's not hot...but the longer you are blowing your car off the warmer it gets. I have never measured the temp, but it does get up to where you notice it holding the end piece. I wouldn't say it becomes "painful" but you notice...
I heard some people say that they didn't like that fact because sometimes it causes evaporation of the water as fast as it blows is off. To be honest, when I was washing my black car in Tulsa Oklahoma (never measured the water, but it was hard enough to leave spots on the car if not dried) I DID feel like I noticed this happening a little when trying to blow off a large flat panel (ie vette hood). It was unequaled by anything I've used as far as blowing water out of crevices etc. like side mirrors or side marker lights... it was GREAT for that. It blows HARD. If you let go of the hose with both motors running it will flip around like you'd think of a firehose doing....
Was it worth it... hmm... I can't decide. I also used a CR Spotless filter on my black car and I think the combo was great. If you are fighting hard water... it WILL evaporate the water on large surfaces leaving small spots. Again, this was on my black car. I'm just a hobbyist, not a professional so I only used it on my black car... so with other colors it might be great... sorry I haven't used it on enough cars for a great review... but that's what I can add as far as master blasters go.
It is definitely a great tool if you have a car, or detail cars with lots of crevices or body mouldings etc. that tend to drip down later after you've dried your car.
Rob