Horn is the future German number one IMO. Only 22 now, 6'4, is brave and very acrobatic even for his size. Im surprised we haven't been linked with him tbh. We haven't even been linked to Leno but his link to Real Madrid have pushed many fans to name him as a possible buy for United. I honestly didn't hear too many English/PL fans talk about him specifically before that.
They are both talented and I think that under the right tutelage they both can become very special. At the moment Leno is more experienced, he has been tested at a higher level but I have no doubts that Horn can confirm is potential.