Bear in mind there are many factors: fabric, design, fit and function or use. Fit really is dependent on brand. Many brands use the same or similar materials, even design. Their fit really can vary. For example I used to have a very nice softshell by Montane. Absolutely perfect fit for me. I replaced worn out ones with the same jacket. They changed names and colours, tweaked the details but same jacket. Then I needed another one and they changed the fit. No longer any good for me. Then there's other issues. Keela used to have a real quality issue regarding size control. So much so I used to have a local retailer of their stuff to call me whenever they they had new stock and a certain model of trousers was made with longer legs. Seriously identical waist size and model trousers used to have 2" difference leg length. The story I heard was the next generation of the family who owned Keela was taking over production. The son of the founder was really into production and was controlling it better. Stopped buying after that because the trousers became too short for me. Off topic sorry but I'm just trying to illustrate how you need to pay attention to brand sizing.