I think it depends in part on height and body type modifiers and the rest of the outfit because it's all about proportion. I have blazers both long and shorter. The one in the first picture hits me around my high hip -- it can be worn with dresses, wide legs, and slim jeans. The next two are longer, closer to low hip length. For this to work on my short legged self, I like a jacket that emphasizes the waist a bit and it's most flattering if I can wear a column of colour or a tonal look. Obviously with the bright pink jacket that's not likely and it's also a bit of a more traditional "mannish" cut (less sharp shouldered and waist emphasis than the Reiss) -- so I almost always wear it with a bit of a heel. I never wear these longer blazers with skirts or dresses.
The next four jackets are various styles but all are shorter. The blue military sweater jacket is quite cropped, like a short cardigan, really. The red one is a bit longer. Both of these work well with wide legs, culottes, etc. as well as a slimmer trouser. The tux jacket is long enough that it does not look great with a wide skirt (but will work with a sheath). The tweed jacket is a little longer on me than the model.
I tend to like motos and denim jackets a bit cropped -- it's just easier to wear them as I would like then.
