This is hard for me to say, and I'm sure it won't sit well with many proud Argentines, but the beef you get in restaurants in Argentina these days isn't as good as it used to be. On a trip to Argentina this month, my wife and I kept ordering steak and kept saying "it's not as good as it used to be." Our first visit to Buenos Aires was 29-years ago.
There's apparently a reason for this. Economics. Today's Argentine cattle don't graze freely on the pampas before slaughter. Rather, they're fattened in feed lots -- just like USA cattle are. Which probably explains why Argentine beef now tastes a lot like US beef. While I hate to say it, the sub-$25 steak you get at a traditional Buenos Aires steak house might not be better than the steak you can get at a decent US chain restaurant, like Longhorn (audible gasp).
Folks who don't remember the old days (like pre-2000) will undoubtedly think Argentine beef is still quite good. And the cooking techniques in the restaurants tend to be excellent. I also don't know whether "luxury steak" meals -- like at a place like Cabanas Las Lilas -- is better than a $50 steak you can get in the USA. But if you're heading to Buenos Aires primarily to eat steak, maybe you should move onto Italian after a day or so.