I agree Chinese airlines are improving - in fact they've improved considerably over the last 5 years. But for me, a lot of that comes down to the introduction of flat beds, which is now the standard on long haul.
For me, a good bed, edible food and a cold drink is all I need.
As for service, I don't think I can fault the crews in terms of effort. Indeed some crews have been outstanding, equal to some of the best carriers. It's a pity they are limited by the soft product they have to work with.
Would I be happy paying top dollar? No. But for the price the Chinese carriers these days are pretty good value for money.
I quite like Spring - but have only flown in Spring Plus. I find it a pretty good deal. Similar to Euro biz class in many respects.
Juneyao I quite like as well. They have some pretty cheap fares and the service in business class is good.