I'd definitely still consider those "good". Most of my battlers are in the 1500-2500 range, with a handful hovering in the 2800-3500 range depending on species and IVs.
To me, a Pokemon is good if its CP is high enough, if it has really good IVs and won't take too much investment to hit good CP, or if it's some combination of these two things. I've always been a stickler for perfect IVs in main Pokemon games, so usually I hold onto something with amazing stats in GO as well.