>>9350999
A transfection reagent is just something that gets DNA inside your cells (PEI is a chemical and AAV is a virus). Open in this case is open source (ie everyone can see exactly what's in, unlike proprietary plasmids which are trade secrets).
People in science almost always overhype their results/tools/etc to the public to increase exposure and possibly funding. It's just marketing with no substance. Besides, there's a much bigger catalog of plasmids on Addgene.