So many factors..
First off, "attractive" is subjective.
The whole package, however, is a subtle play of curves. There are good heels and bad heels - good heels take care to load the foot bone structure in a way that doesn't cause damage, and are engineered properly (there are a *lot* of mechanics involved in a decent high heel), and there is a "maximum height" above which no woman should go (easily found - if the front leg goes straight into the toes as one straight line you are really at the maximum point - go beyond that and you're looking at damage) - depends on the feet involved.
Bad heels do not distribute pressure properly and should be banned as torture devices. Platforms tend to quickly trend towards being crap because the height throws off the delicate balance required, and the designer's idea to put a heel fully at the end of a shoe is stupid as well (the heel should really be under the body's weight or they will hurt when walking as you end up creating a lever effect). There is a reason why the classic spike heeled pump has endured so well over the years as a design - from an engineering perspective it offers the best balance between support and height. However, it needs someone with trained ankles.
Price is not an *absolute* measure of quality, but if you like the elegant sight of a woman in heels and she is your partner I suggest you don't skimp on price or complain about it - it's not design you pay for, it is (in many ways) feel good factor.. With boots it gets a bit more complex because then you also have to deal with the shape of the leg - a leg with decent muscle development is easier to design for (the "modelling" leg is a tad too underdefined, but that's a personal opinion, I like people with an athletic build that at least throw a shadow).
Anon because I know far too much of this I had friends who had a shoe factory, and as an engineer it's fascinating to see how complex it actually is to create a good pair of heels or boots (it helps having a happy test recipient around :)..