Square D discontinued the all-in-one QO resi services It's Sq D Homeline or go to another brand. Even the QO load centers I've seen recently are plastic junk. The place that the breaker snaps onto (opposite the bus stab) used to be steel, now it's plastic
If you want "Zinsco Quality"* go SQ D, if you want good quality use a Cutler-Hammer type CH.
* I might raise a few hackles w/ that statement but SQ D and others have built their panels so cheaply as to deserve that comment, QO breakers are a fine product, but a chain is as strong as its weakest link.
The plastic interiors started when Gould Inc. intoduced the I-T-E EQ III loadcenter about 1979,but I do have to admit the split neutral in those panels was a nice upgrade.
never had or seen a problem with a QO, plastic seems plenty durable, breakers clip on nice and tight, I really like the way that most of the buss is covered, keeps you from getting zapped by all that exposed metal...