22" (55cm) x 14" (35cm) x 10" (25cm) is the maximum permitted carry on size on AR. This is in fact pretty standard across the industry.

However, the maximum weight is only 5kgs in economy, 10kgs in Club Economy.

I recently flew 5 segments domestically within Argentina on AR. Club Economy (Z class) was only 10% more, so I booked Club Economy in the front of the bus. It's well worth it as the checked baggage allowance was only 15kgs for regular economy. (30kgs for Club Economy). The seat is similar to North American First Class.

As a Club Economy passenger, I did not have any problem with both my cabin and checked bags.

Unfortunately, none of my flights was on the EMB. I assume that the configuration will be similar to those in other parts of the world which a 22"x14"x10" cabin bag should fit.

Make sure to call AR to register both your mobile phone and e-mail address on your PNR in case of flight cancellation or delay. They are actually pretty good in sending you alert messages. One of my flight was delayed an hour and I received an e-mail on my mobile phone even before I left for the airport. They also protected me on my connecting flight without me having to ask.