I have also gotten conflicting advice, similar to what you have heard. I'm no expert, but I'll tell you what I ended up doing which seemed to work out pretty well, at least so far. We bought a ~100 year old home six months ago that we're just getting around to painting now, after rewiring. Most of the trim is painted with what seems to be a high gloss oil-based paint, and a much of it (especially doors and baseboards) is quite dirty. The only trim I've painted over so far is a few doors, but I'll be starting on the rest of the trim in a couple weeks. For the doors, I scraped off just whatever bits were already flaking off, then washed them really well, and then used "liquid sandpaper". If your trim is glossy you may want to use liquid sandpaper to remove the gloss. It's not a paint stripper, so you won't be left with messy globs of dissolved paint. It just removes some of the sheen so that the new layers bond to it better. Then I primed with an oil-based primer. I have used both latex and oil primers in a previous home, and the oil primers always seem to bond better. Then painted with Regal Select Semi Gloss. I haven't tried Natura, but I might... Anyway, I would recommend liquid sandpaper rather than sanding as long as the old paint is basically well-bonded to the trim, then oil-based primer, than latex paint. I'm curious what suggestions other people have..

There is rarely a big price difference in a painters quote because of paint costs. Even if the paint costs $10 more per gallon, if he uses 20 gallons, that's only a $200 difference. The difference in labor probably isn't that great either...I suspect the painter wants to charge more because he does not like using oil (neither do I), and he's hoping you will choose the latex because it's cheaper. The big difference in using oil is that you can't do 2 coats in the same day because of the dry time. It takes just as long to apply the oil as it does the latex, and if there is a difference in application time, it's small.

I have used both oil and latex paints on kitchen cabinets in different houses, they were ok, but I love, LOVE, LOOOOVE Cabinet Coat paint! It wears like a dream, and feels better than anything you have ever felt in your life! We have 4 boys and two pets and nothing they could do to it damaged it. It is not too shiny, not too flat and didn't yellow in the 4 years we lived there. The only catch is that it is a tintable base but is only available in lighter colors. In my last house, we painted the perimiter cabinets with Cabinet Coat paint and the darker island with BM Impervo (oil) the Cabinet Coat cabinets win hands down! Anything and everything wipes off easily with no staining. I don't know if I've mentioned it, but I love Cabinet Coat paint :-) Here is a link that might be useful: Cabinet Coat Paint

You may have had a different experience, projects. I know what I have done in multiple homes, been advised by pros and what the manufacturers instruct If I recall correctly, BIN is the Zinzer shellac primer that is similar to the KILZ shellac. I have only used the shellac primer for two projects (and maybe leftover on some that followed). The first was when we had to chose between going over wallpaper on the one hand and replacing the sheetrock on the other -- it was that bad. We were advised to use the shellac primer to permanantly bind the paper to the drywall and chose that route, figuring we would replace the sheetrock if it didn't work. It did, but it was stinky and messy to work in a small powder room with that stuff. The other was to deal with a post-animal problem we wanted to make sure we never smelled again. Once more, stinky and messy stuff to work with, but it worked. Without special circumstances, I always recommend the KILZ water based or Zinzer Bulls Eye 1-2-3 (I've seen it as just 1-2-3 too). It is much easier to work with and to clean up and they say no sanding necesssary. Do I degloss anyway? Sometimes. Depends on the project, but I can tell you that stuff doesn't peel off a clean surface. Now, cleaning the surface is another issue.