We can say steam model locomotives in N scale offerd before 2000 are generally poor runner with many flaws and not well detailled; most of them are from the prehistoric age of the N scale locomotives; the Atlas-Rivarossi family is great but really out of age against a today N scale steam model.
On the other hand, generaly, any N scale steam locomotives which are produced after 2000 are excellent runner for the most and extremely well detailed.
Kato opened the road with their mikado in the 90’s.
Bachmann Spectrum line since the release of the consolidation has offered a N scale steam locomotives family which are outstanding in details and the most of the family run well out of the box.
Model power had athonished everybody with their N scale steam locomotives; they run well and are well detailled; they have no good electrical contact on the tenders but Bachman Spectrum ones offered separetely are an excellent alternative.
Life Like-Walthers had offered also exquisite N scale steam locomotives which are perfect runner; the Life Like N scale line of locomotives was buy by Atlas in 2017 but since the deal none Steam locomotives of the Life like Proto 2000 Heritage were offered by Atlas.
Unfortunately, the model of the 0-8-0 switcher which is a real jewel will probably never offered again since tools and molds of the model have dissappear in china.
Atlas has offered an exquisite RTR shay in N scale which is a excellent runner.
Athearn has offered some models too, the Challenger and the Big boy in N scale are outsanding models which run particularly well.
Fox Valley and Intermountain N scale steam locomotives are oustanding and perfect runner.
BLI N scale steam are also perfect runner with outstanding details, all are DCC with sound.
Most of the models from Bachmann Spectrum, Model Power and Life like were offered in a second run and are DCC , some with sound.
Hope to see more steam models to come in N scal