BGI

It went well.  We bought the door ourselves, doing the measurements ourselves, with the intention that my husband would put it in himself.  Then when we looked at the instructions and looked online for additional youtube instructions, we started thinking it looked a bit too hard, and we even started thinking we might not have measured correctly.  Basically, we chickened out.  When Mike was here at the house measuring our windows as a sub contractor for another company, he noticed the storm door laying in our porch.  I shared my concerns and he checked the size and said the size was fine, and he could put it in a few weeks later when he came back to put in our windows.  Which he did.
When he was installing the storm door I realized how hard it was to do, and how good it was that we had not tried to do it ourselves.  We would not have been able to do it well, and if you damage the door you can't return it, of course.  And not doing it well would have defeated the purpose of having a tightly sealed storm door, especially living here in MN.  He did an excellent job in every way, put in the "thing" that holds the door open when you want to bring something big in, etc., all things we would have struggled with greatly.  I would recommend BGI without any hesitation.  :-)