People often comment how it's pretty difficult to understand Argentinians when they first arrive here. I never really had that problem. Maybe because I've been around in the Spanish-speaking world and have heard many accents, or because I myself grew up hearing that accent. But either way, you always encounter some people who speak very clearly, and others who mumble and use too much slang.
One reason people have so much trouble here is because of the grammar form of "Vos." Vos is an archaic form of speech that hardly any cultures use. Usually, it is used in very intimate situations and mainly with family members only. Otherwise, it can be almost insulting. My mother has made this mistake when speaking with Latinos from other countries at work. Even in Ecuador they use Vos in the Sierra, but only in place of "Tu." However, in Argentina, Tu is not used, and Vos has its own unique conjugation.
In all honesty, I'm still learning Vos as I go, but I think it's the easiest form to figure out. There are no irregulars, and you simply change the ending of a verb. For example, take the verb "Comer," meaning "To Eat." Normally, you conjugate it in the 2nd person as "Comes", or You eat. In Vos, it is simply "Comés", with the accent on the last syllable. The same goes for endings in -ar and -ir.
*I understand this might be confusing for those who don't speak Spanish, but stick with me, I'm going somewhere with this.
Anyway, the commands are a bit different, with the emphasis staying on the last syllable, but without irregulars. Example: Poder = To Be Able To. Conjugated with Tu, it is "Tu puedes". In Vos, it is "Vos podés". You don't have to worry about conjugating the 2nd person form. It is much simpler.
So the whole point of this is that if you want to learn Spanish, I think it might actually be easier to come to Argentina and try to study here. No one outside of the Argentinian world will really speak this way, but they'll all understand it. As you get more accustomed to Spanish, you can pick up Tu easily enough. But if you're frustrated in Spain or don't understand Mexican Spanish, give Argentina a shot. You might find it to be a lot easier to learn a form with no irregular verbs.
For more information on conjugating Vos, follow this guide.