Seats are definitely more cramped. I think business on I2 is about what coach is on IB. Aside from that, I have found the crews to be delightful.

That said, I have also had good experiences on DY. Obviously no business class, I just dislike T1.

I mean, for the J fare, since you have status, I don't know if I would pay it to be slightly less uncomfortable for a few hours since you have lounge access and parking and all that already. But hey, to each their own and it's certainly a reasonable price.