Canon - RF 24-70mm f/2.8L IS USM vs Tamron - 28-75mm f/2.8 Di III VXD G2

These two are nearly even on the Mars Score (55.3 vs 57.1). The decision is not about overall quality — both clear the bar — it is about which specific trade-offs fit your use.

Pick the RF 24-70mm f/2.8L IS USM if you care most about optical stabilization. The biggest gaps in its favor are optical stabilization.

Pick the 28-75mm f/2.8 Di III VXD G2 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight, min focal, max focal.

Both ship with comparable weather sealed, so those specs do not separate the two — focus on the differences below.

Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.