original quote shortened for brevity ..
Sir Ruben,
A nicely done review, however can I point out that you are using a Touchwiz version of Android and not Google's vanilla version. Issues like lag, app fc's and that sort of thing are because of Touchwiz, not Android. Cut through all that TW bs, and you get a very fluid, fast and crisp piece of kit.
I hate what Samsung have done with Android and their layers of excessive crap U/I. I use a custom AOKP ROM on my S3, and there is a night and day difference. I love Samsung's hardware and coupled with a professionally done and optimized ROM or Vanilla Android, you will be in heaven. Once there is a stable ROM for the S4, i highly recommend dumping Touchwiz and all the crap Samsung adds with it.
Good luck and thanks again for a nice review/comparison. Cheers.