For a reality show, probably one of the least objectionable for child content. Some usually minor language, minimal physical violence, and minimal sexual content. The worst part is the verbal abuse between members of the teams or between the actual teams. Some contestents are very verbally abusive.
Also of note, with each season, the verbal abuse / language / sexual content / product placement seems to get a little worse or more graphic due to casting or editing.
For kid appropriateness, this is hit and miss .... some episodes are very clean, while others are a little more concerning.