Or does it make an artist more respected/relevant

Ruins. See: Nicki, Mariah, Nicole, Jessie etc.

I think it depends on the artists really. But in most cases yes

Not if you're Britney or Maroon 5

Well Jessie J is kinda slaying right now.

Their careers are already ruined, so no.

I hope not

The Voice definitely hurt Jessie's career at the time.

She brought a new meaning to the word cringe. I mean: "They have to bring it.com!"

Weirdly it seems to help male judges more over the female ones who seem to bomb afterwards. The Script and Maroon 5 hit new highs after their front men were judges.

Woman get scrutinized for everything they say ,do, look at etc so female artists tend to get a negative response from this. Whilst with men it seems to work since ppl feel "closer to them" and when a male judge says something controversial ppl take it as a cute bluff and funny whilst With women the GP drag them to the pits and back .

Well Cheryl's career blew up after X-Factor which helped her so much but I'd say that it was because she was kind of viewed as a "national sweetheart"