I can talk with a mexican with no problem, despite that they have different meanings for some words.
Argentinian spanish is nearly the same to uruguayan spanish, but there are some things that we don't have in common. In grammar, it's all the same. But argentinians speak with other tone.
Note: Argentina has a lot of regions with differences in their spanish: the south, the west (close to the Cordillera de los Andes, there they speak similar to chilean people), the north (next to Bolivia, there they speak like the bolivians do) and the east side. In this zone is were they speak similar to us.
It's really nice to speak more than a language, I'm not a good english-speaker but I hope that you understand me with no problem.