Shemonaika was okay for us last year (we did Kaz->Rus), bit slow but it was a weekend, waited about 40mins to get into the Kaz control and about 30 to get into the Russian one. Russian side were pretty uninterested in everything, Kaz side got very exited about our concurrent passports (wanted to see Russia Visa and it was in the other passport), a bit of explaining to do but all okay.
Yalama border crossing was quite good for us last year (Kaz->Uzb), rode around all the trucks straight to the border gate and they let us straight in.
Kaz was really easy (but as above freaked a little when they saw concurrent passports), Uzbek side was really good modern crossing and relatively friendly staff, including some English. Made us unpack everything, but were very friendly and courteous about the whole thing.