Currently in the USA it is just a matter of preference. It is more common in the show ring to have the cropped ears. In the past exhibitors felt that Judges were more apt to choose the cropped ear over a natural ear set. This is changing a little bit. You see some of them doing very well in the show ring. We've had a couple of our show giants that will be in the ring with natural ears.

   We are finding more and more people expressing that they would prefer natural ear on the pets rather than a cropped ear. You need to discuss it with your breeder. "Natural" ears also need a little taping care in order for them to stand well for the conformation ring. It is more a matter of preventing them from folding. Not a difficult thing to do but it does need a bit of work.

   While I myself tend to prefer the look of the cropped ear they do require extensive care.

Shaving, cleaning, taping, Posting and preventing infection until they stand on their own, Treating the spot infections, allowing ears to air a day or two, cleaning posting, then re-taping again for 4 to 5 days, Starting the whole process again. This can take many months to stand correctly and if you are not consistent they could end up flopping over or on the head.
This will take time and patience of you and your giant. I do not mean to discourage people from cropping but I just think people do not understand all they have to do. Taking the tape and post out of the ears may upset him at first. Some dogs get very sensitive about people touching the ears when they are cropped.

If you have a supportive breeder even a novice can do well.
  Why put the dog through all that trouble, if you are not consistent and then one or both are going to flop over and you think it's cute.

If you are not up for the care you have to take you should just leave the ears natural. You should discuss the pros and cons extensively before deciding on cropping the ears.

MW