It really depends. There are things you need to consider. Ex:
Does your team need... a diver, a tank, a peeler, etc.? Does your champ fulfill what your team needs?
Do you know it well enough to pull it off? Have you practiced it a ton or did you just play 2 pve games (if that) and see it on some YouTube vid by a streamer or pro?
Will it work vs their team comp if they play effectively? Ex: Shaco jungle is nice... if the enemy doesn't get a lead, group 5, and push towers. If they do get a lead, group 5 or 4,1 with a tank/bruiser, and push towers and have enough hard cc, you die for engaging, your split push isn't as effective as theirs, and you can basically do nothing. That's just one basic analysis example, so hopefully you see what I mean. Take a look at the recent article by Riot and their analysis of the kha pick in 2 games for more examples: http://www.lolesports.com/en_US/articles/na-lcs-2017-week-2-what-exactly-team-synergy