500 if using JD oil
250 if not JD oil, because JD oil is that much better.
400hrs for Agco/Massey/Challenger SCR Engines regardless of what oil it is
600hrs for CNH regardless of oil
These are for Large Frame High Horsepower Row Crop Tractors.
I can say on our Agco With SCR after 380hrs the oil was still clear.
So which one is more to maintain? Both. The DPF/EGR motors need their oil changed slightly more often, and need their DPFs cleaned around 4000-5000hours IF THEY MAKE IT THAT FAR!!!. Ask a trucker about what they were told about how long their DPFs would last and how long they did last.
The SCR motors require the DEF filters to be changed in that 4000-5000hour range as well. Ive changed one and its much simpler than removing the DPF in my opinion. However you have to deal with the DEF fluid itself which simply doesnt work for some people. On-road its a no brainer, but off road it can be hard.
Fuel economy on the SCR versus EGR motors that I have seen has been phenomenal.
Im an advocate of SCR, but I understand the other concepts and their advantages,
heres an interesting read
http://www.tractorlife.com/Maintenance_of_Tier_4_engines.php?action=results&poll_ident=9