The 28 and 280 were always 7/8th scale 34's. I would agree with the post above in that they are neither superior to the 34, just different. I do contend that as far as .177 calibre Diana's go , I would have the 34, but in .22 I would be happy with either (standard guns).
I do not think the stocks are inferior, either, but saying that the ambi "hump" on the 280 is a bit of an acquired taste on the eyeballs. The basic non -stippled 280 Classic is still a nice looking, if plain, gun.