IMHO, good, but not breathtakingly realistic. It's small and big strings combined, always the easiest way to make them sound good. They sound quite like the preset strings on the Krome, where I liked the small ensembles, but didn't like the big sections very much. It's too short here to say something definitive about the big sections, but I guess Korg didn't sample any new strings for the PA-4X. It's always expensive to sample a big strings orchestra, dozens of players, a concert hall, tone engineers to be paid for several hours or days. But hopefully the 400 MB free sample space could be used for more exclusive strings, maybe from Karo Sounds (although presently they just have strings for Kronos)...