Depends on two things really
1) How tired I am. This determines how much energy I spend paying full attention to the anime in question. If I'm tired, I'm going to turn the English VO on and veg out.
2) How annoying is the VO cast. There are some really good VO out there, and then there are ones that just get on your nerves. For example, I love Ai Yori Aoshi, and the Japanese cast was phenomenal, but Michelle Ruff's portrayal of the main character Aoi Sakuraba just grates on my nerves. Her tone of voice just didn't fit the character.
The opposite is also true. I prefer Tiffany Grant's portrayal of Asuka in Evangelion over Yūko Miyamura, and this is coming from someone who was watching Evangelion long before ADV picked the series up for an English dub.
1) How tired I am. This determines how much energy I spend paying full attention to the anime in question. If I'm tired, I'm going to turn the English VO on and veg out.
2) How annoying is the VO cast. There are some really good VO out there, and then there are ones that just get on your nerves. For example, I love Ai Yori Aoshi, and the Japanese cast was phenomenal, but Michelle Ruff's portrayal of the main character Aoi Sakuraba just grates on my nerves. Her tone of voice just didn't fit the character.
The opposite is also true. I prefer Tiffany Grant's portrayal of Asuka in Evangelion over Yūko Miyamura, and this is coming from someone who was watching Evangelion long before ADV picked the series up for an English dub.