The radiator is actually a very good quality radiator and it's got an aluminum core with plastic side tanks which is supported at each end by plastic tabs that are part of those side tanks and that's a big problem IF the car ever goes over a high cement parking stop or hits Ice walls in winter as the support tabs just break off. One needs to be aware of that so as to not get too close to items that'll damage the radiator. On occasion, I've seen a few where the o-rings between the tanks and core leak too but I've never known of a radiator shop that'll attempt to fix those.

$650 sounds steep to me too IMHO.