We have only taken the Buquebus ferry from Montevideo to Buenos Aires. I recently came across Colonia Express, which also offers service from Montevideo to Buenos Aires (a bus from Montevideo to Colonia and a 50 minute ferry from Colonia to Buenos Aires). You can get tickets for $78 Argentine Pesos each way (which is about U$S 20 each way). I was just curious if anyone has taken the Colonia Express and what their experience was.