I haven’t seen it for sale recently, but it isn’t something I sought out after my seed pack ran out.
As I remember it was OK but I tend to buy seeds for the oriental greens family on whatever website I am doing a main seed order on, so the ones I grow vary year by year. Most are the kinds for stir-fry, but I did grow Chinese Violet Cress for salad leaves last winter and that was good. I also like the Sarah Raven autumn and winter salad leaf mix. Both were grown in pots over winter in the unheated greenhouse and lasted until early March.
For summer I usually go for proper lettuces and plant them out on the plot. Most oriental greens or salad leaves are tricky over summer as they bolt so easily.