Excellent information in that link. At least toward the latter half of my painting career I seldom had to give competitive estimates anymore but understood people needed to have an idea of cost. I found my role to be helping them define what they wanted out of finished product and got them to think almost like architects or others that spec materials.
Having a statement of what you expect out of a painting project and the type of materials and workmanship you expect to be used will keep everybody on almost the same page and make it a lot easier for you to get estimates you can actually compare.
If you just ask what it costs to paint the house you open yourself up to too many variables and you will not be able to accomplish but an apples to oranges bid comparison. So zero in on them and make notes of variations suggested by painting contractors but make your basic decision on how everybody bid to the original parameters. Then check references if important and drive by and see some other work.
We in the business all started somewhere and were willing to cut deals to get going. I don't think any of us would deny up and coming REAL painters a similar shot. And most good painters, even in this economy, seem to stay pretty busy and might have to line you up in sequence for an exterior job. And then, of course their are horrid places like College Painters that will put something disguised as paint on your exterior, shrubs, walkways and dog for next to nothing. House will look great until it rains once and it washes off.
As for what I would look for in bidding for you? What paint is on there now and how much is peeling off. Are there stucco cracks or surfacing that needs to be repaired prior to painting? Water staining along the ground level? What paint is on the trim, soffits, etc. and does it need repairs? Would I be dealing with any gutter issues before painting? What kind of longevity are you hoping to get out of the paint job and what quality of paint did you have in mind (I probably would walk away if you were just painting to sell)? How many color changes and are they intricate (thinking of trim on older antique houses more than yours I guess)? What is your timetable for the project and how flexible can you be?