Mango makes the most rational affordable blazer — linen that hangs properly and doesn't require dry cleaning for every wear, a shoulder that's properly set without padding, and a length that works over both trousers and jeans. The buttons are properly finished, the lining is present rather than absent, and the seasonal colours include the cream and camel that have genuine longevity.
The French brand that dresses Parisian women who want considered rather than obvious. Sandro's blazers use properly tailored construction with half-canvas, a fit that's neither oversized nor fitted but perfectly in between, and fabrics that look expensive because they are. The Prince of Wales check is the pattern that never dates.
The Row makes the most considered blazer in contemporary fashion — the wool is from the finest Italian mills, the construction is full canvas so it moves with you rather than on you, and the cut is developed over multiple seasons of refinement. Put it on and the proportions are immediately, obviously correct. The blazer that makes every other piece you own look better.