Masako Nozawa voice-acted for Gokuu and his sons and male relatives all the way from DB to DBGT (except Radittz). That includes kids and adults, each with individual voices. She can even sing in her character's voices... (Goten singing's disturbingly cute!) A lot of people are put off by the fact that she's a female voice actor, acting mostly male roles. You can't really tell. I think her talent at voice acting really makes a difference to the way each of her characters come across. I think that's one of the reasons I stopped watching the dub. While I know a lot of people think there's nothing wrong with the dub voices (the scripts don't help either), the main difference is the characters seem to have lost a lot of their innocence. Masako Nozawa seems to fit the role perfectly.
Another thing I find Masako holds above the dub is the ability to do battle cries, and that gives the battle scenes a lot more credibilty.
 

Hmm... I suppose the biggest thing that separates Japanese and English-speaking voice actors is training and experience. Most of DBZ's American voice actors seem to have had few (or no) previous voice acting roles, and that generally means that it takes them longer to get used to characters and act their parts. I personally avoid the dub most of the time, so I know a lot of people will dissagree with what I say here, but I don't think much of Kara's voice acting skills. (That's nothing personal, the only FUNi voice actor I've liked so far is Android 18's) I just hope she'll improve with time or something...

I'm afraid I haven't been able to find out anything about Goten's Chinese (Cantonese dub) voice actor, but as I've seen Movie 11 in Cantonese I can at least give a review of his voice acting.

Goten's voice in the Cantonese dub is uncharacteristically deep, most likely because Gokuu's is also very deep and the company wanted the voices to be consistant. Trunks' is higher than it is in the Japanese or English dub, so when both Goten and Trunks talk it's pretty weird; rather like their voices have been swapped around.

My opinion is that young Goten seems a lot less cute and innocent with a deep voice, so I don't really like his voice in the Chinese version.

Name: Brigitte Lecordier
Gender: Female
Voice Acting Roles: Gokuu, Gohan and Goten as children, and a lot of other popular French characters. 

I've only heard Brigitte Lecordier's Goten voice in a few movie and sound clips, but from what I've heard of it, it's very cute and much like Masako Nozawa's. Most sources seem to say that the French dub is pretty good, and imagine that is the case.