I like the vignetting effects. So no issue for me...
Why not give the lenses a try at the Wisma Service Centre? Handle the lenses and decide which one is the best for how you shoot? It will give you an idea of the weight, reach of the zoom and the handling. It will help you make a decision. Ultimately, it's not possible to combine ultra-wide with telephoto... many years ago when I first started out, I always hoped that someone will make a lens like that... given up hope already actually... a 16-250mm lens for APS would be perfect... but the best is a 18-250mm so far... it's like in the film days when I had a 28-80mm and wanted something wider and longer. There was the 24-135mm Tamron, 24-105mm Minolta and the 28-300mm Tamron. It was a decision between wide or long... better IQ or better zoom reach... same dilemma... finally I decided that there was no all-one-solution and I needed to carry more than one lens anywhere...