I have been using Dip n Strip for a few years and always had good results. I just did two more doors, 120 year old yellow pine. They came out absolutely beautifully and Jim was very help in working with on stuff like extra hardware and logistics.
They really get off the paint without damaging the delicate features of the wood underneath. I always clean up details and stuff before I varnish and I get really nice results. I used to strip my own doors and could never really get them to be as good.