Yes, I use mine for fries, courgette or celariac. Also made fried chicken, but used a shallower pan rather than full immersion. I know Atkins book advises to avoid deep fry, but I've had no problems thus far.
You can, but I don't, but that is mainly because I am obsessive and wouldn't know how many calories it added.
Another reason is that the oil used to deep fry is usually vegetable or sunflower oil which provides omega 6 and the western diet is woefully deficient in omega 3 fats and overloaded with omega 6.
If you try it, please let us know how it goes. Would be a useful option. I'm trying to adapt several recipes not to deep fry but i'm yet to attempt any of them.
Ok cool I'm gonna get down a stone and then give it a go just incase it stalls me, I don't think I'd use it all the time maybe 1/2 a week and think the key would be in the oil or with the fryer itself!
Ill keep you posted