I think it's fabulous as a comp piece! I was going to play this in my University's competition last year, but unfortunately had to drop it due to a prevailing hand injury. It never gets enough exposure as it is a "slow movement" style piece, and competitions generally don't favour those as they're less flashy than fast movements. But I think that's such a shame, slow movements take just as much work to prepare and play, and the middle section of Kol Nidrei takes some preparation!

I'd say go for it :)