Digital camera world posted its full Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD review here, and they found that the lens did not have many shortcomings as you can see from the excerpt below:
Ideal for travel and walkabout photography, the Tamron 18-300mm gives an effective 16.6x zoom range of 27-450mm on Fujifilm X and Sony E mount APS-C format mirrorless cameras. That’s quite a stretch, delivering everything from fairly wide-angle coverage to super-telephoto reach at the twist of the zoom ring, without the need to carry multiple lenses and switch between them. So-called ‘superzoom’ lenses are often a compromise but the Tamron does pretty well in terms of image quality and all-round performance.
Pros
+Mighty zoom range
+Impressive autofocus and stabilization
+Short minimum focus distanceCons
-Edge-sharpness could be better
-Heavy barrel distortion when uncorrected
-Color fringing at longest zoom setting
Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD:
B&H Photo / Amazon / Adorama