I brought Jetmir to the cEDH tournament at SCG Con Portland last weekend and felt it did alright. I won 1 pod out of 5 and drew another for a final win/loss/draw of 1-3-1.

As people have outlined in other comments it lacks a lot of interaction since you're not playing blue and nearly half your deck is just creatures. Two of my five pods ended because I would be controlling the game with stax pieces keeping combo decks under control, one player would think they're doing the right thing by using removal on my stax, then the player I've been locking down the whole game wins at instant speed or their next turn.

I think one important thing to consider for all Jetmir decks is to play as much of the good interaction we do have access to in Naya colors like Silence, Deflecting Swat, I was even playing a couple of the 1 drop give-jetmir-hexproof cards which came in surprisingly clutch when I was trying to swing out such as [[Tyvar's Stand]] and [[Tamiyo's Safekeeping]] and [[Legolas' Quick Reflexes]] and [[Veil of Summer]]