If you want a great cheese (sorry... puns are my Mother Tongue) to add to pasta, but Reggiano is a little too pricey... Grana Padano is a wonderful alternative... It's not cheap, but it's cheaper... and very flavorful... Not Parm, but then, nothing else is. And, though I've done it myself in the past, I'd avoid the Argentine and domestic "Parms" - just trust me on this one - a little bit of the good stuff beats out a ton of the... not so good stuff! Not that those 2 are bad... it's just that if you're expecting Parmesan, you won't be happy.
A little illustration... 100 years ago, when I was a lad, I went to a cocktail party at a theater where I was working. Around came a tray of peanut butter cookies... you know, little round beige things with the marks of a fork across the top. I was a little surprised that there were peanut butter cookies at a cocktail party... but what the hell. So I took one and popped it in my mouth... You guessed it... a sharp cheese biscuit. I tried to be discreet as I gasped and choked. Years later, I've arrived at 2 conclusions: 1) I'll bet the cheese biscuit was pretty good. And 2) Don't ever be guilty of false advertising... if it walks like a peanut butter cookie, and quacks like a peanut butter cookie...
Anyway, I think the Argentine and domestic Parms are probably OK... but they are NOT Parmesan!