The pred is usually between a typical firebird and typical C PD. I have some preds that are flat as **** and they are gross meathooks. My favorite are the normal preds, which fly exactly like a first run PD, or an extra overstable C PD. So of course Preds can beat into understable. First they'll start flying like a typical C PD (my personal favorite stability), then like a typical thunderbird, then like a worn thunderbird. If you like to purposely cycle do not buy Z, they take FOREVER to wear. The ESP has fantastic grip and will cycle significantly faster, but still slowly lol. Don't expect to have an ESP pred that flies like a thunderbird unless you plan on throwing it very fast and on every hole you play. I just use a Z pred and a Z avenger (what the thunderbird copied) instead.
The problem with preds for most people is that they don't like the way the bottom of the rim feels in a forehand grip. It feels money in a backhand grip but in a forehand grip it feels a little sharp. It releases cleanly and flies great, but people think "why should I forehand a disc that feels a little sharp?"