Try to keep away from Alquisur 4x4 car rental agency in El Calafate. They will try to make a small fortune on you in any possible way.
Last year I wanted to hire a car from them and was requested to pay a 30% advance deposit, consisting of 500U$D, which I did more than 2 months before the planned trip. Unfortunately we had to cancel the tour a month before due to a sudden and very serious operation my wife had to undergo urgently. I notified the agency 4 weeks prior to the rental, and they had plenty of time to get other renters and no real damage was caused. They agreed though to reimborse only a part of the deposit, and kept 150U$D. I consider this making a fortune on behalf of others' grief.
There are a lot of dogs roaming around this place. Owners do not chain up their dogs and many are strays. As someone who does not like dogs this makes for an uncomfortable situation.
On the last day of my stay a dog out of no where ran after me. I was not running or looking in his direction. I remained calm because I know they can react when you are scared luckily his owner called him off of me.
I noticed too that many dogs like to chase cars and I noticed several who would jump up on to the drivers window and start barking relentlessly like they wanted to either get in the car or chasing the person away.
Be prepared to pay a high airport tax when you leave El Calafate by plane. It cost us $24 each. I think the tourists are paying for their new airport.
As you go down the steps to get close to the glacier, think about the hike back up.
Actually it isn't as bad as they would like you to believe.