Again, before I went to Buenos Aires, I found very few intelligent evaluations about this GREAT MEANS of traveling between BA and Santiago or Santiago to BA. Here is my own evaluation and experience for the benefit of all future travellers to these two great countries.
I have travelled the world many times and wanted to see a little of both countries. The 2 hour fligth did not make sense to me.
From the Bus Depot Retiro in Buenos Aires (next to the San Martin Plaza and the English Tower and diagonal to the Sheraton Hotel) you can have many bus lines that do trips all around Argentina and beyond. I liked the AndesMar buses but decided on TAC, when I went there to purchase the tickets.
Please READ carefully. I was with my mother and another lady (both 80 years old)and both decided to take this ride as an adventure.
For only $33 dollars per person, we left at 4PM to Mendoza on a 12 hour trip. You do save on hotel, since you travel during the nigth! They feed you, small dinner and breakfast with hot coffe (not a great meal but acceptable) and the seat/beds recline about 150 degrees and are much better than airline seats. The 3 of us rested very good. From Buenos Aires to Mendoza is all flat and nothing to see. The buses have 2 drivers. My plan was to stay in Mendoza the following day and then to Chile and worked to perfection considering I did not have any hotel reservation in Mendoza!
After a restful overnigth trip we arrived in Mendoza at about 9 am (delayed almost 2 hours for an accident on the highway). I took a taxi that for 3 dollars took me to downtown to the Hotel International. I found a nice room (2 of them) for only $45 dollars each and went out the rest of the day to walk around this BEATIFUL city. For only $7 dollars the hotel arranged a city tour of 4 hours (around 4PM) and we got the opportunity to enjoy Mendoza!
Next day we left at 8am ($16 to Santiago with tickets we had purchased also in Buenos Aires) in the same bus line TAC and no meals for a very interesting trip crossing the Andes. To the border to Chile is not that up hill but you can see the Aconcagua. Customs are slow in Chile and we waited for more than 2 hours, but the nice thing about us was the fact that they did not CHARGE THE $100 each american has to pay to enter Chile!?!?. I don't know what happened here but the Chilean Consulate confirmed this cost to me before I left and you do pay it at the airport in Santiago.
From the border you have an incredible trip DOWN the Andes and finally we arrived in Santiago around 4pm. My advise to people interested? DO IT. It is a great trip. I assume also the trip in the opposite way works the same.