yes it's one of the best oil you can buy in USA, expensive but worth every penny... My dad used to be a distributor .... and I used it on everything I drove. I found the Redline tranny oil was better for manuals. which is a full syth. but the engine oil from amsoil was the best of everything I tried but I couldn't afford to keep it up, and went back to Mobile 1 full synth. for the engine.
here in oz I'm going to try PM Lubricants they seem pretty good in the info they sent me and the price is around 50 bucks for the engine oil
You could also give Mobil synthetic diesel oil a go, its supposed to be the same stuff BMW and Mercedes use on their extended drain servicing in their own workshops, its the synthetic equivalent of Mobil Delvac which is also an awesome oil, check the specs.
I have used the Delvac in my 98' VT since new and also a 76' F350 on LPG camper about 4.25 tonnes, runs up to QLD every year, under a lot of load and hardly uses a drop.