What kind of printing are you looking for? Offset? Digital? Are these gigantographs or what?
I just took a project into a printer (del sol graf) the other day, should get it back today or monday, I'll let you know what I think when I see the results.
For somewhere that's close by to me and I just need to see a color check, I usually go to CMD Print -- I think their website is
www.controlprint.com. They have done a bunch of things in our area, they seem to do good work.
I've been to Taller 4 and they do a decent job, do things like stickers as well.
http://www.belgrano.taller4.com/
The selection of papers here is pretty limited so it's not really so much about finding a good printer as it is fnding a printer that has papers you like... they don't carry the range that you find in North America at all...
I'm a professional web/print designer (
www.syndicatedigital.com), but if you're wanting something in Spanish you'd probably do well to use our Argentine designer (he's also more affordable). If you send me more info on what you need I can pass it on to him and you can get in touch.