The 14-150mm Olympus lens is an ordinary lens. It's aperture starts at 4 at ends at 5.6 at 150mm. Compared to the 28-300 from Tamron I really couldn't tell the difference. But I am sure the highly bi ocular detail sensitive friends could fill a book about their differences.
Every lens needs its where and when. I have received this piece of machinery in late november at the height of Rostock city. So light is scarce and indirect. So this makes a very poor lens to work with this time of year.
I shot using an OMD EM1 and that camera deserves a separate post of its own. It offered me high ISO to begin with which I found very usable later on the computer.
One of my most favorite things about zoom lenses such as this one is that you don't need to pack four to cover the whole focusing distance. But winning some space in your camera bag makes you lose wider aperture possibilities.
One of the situations I'd see myself using it is during the wedding ceremony un summer. There is enough light to go around and avoid loosing precious time changing lenses.
Wide aperture prime lenses offer that amazing depth of field. That is not completely lost when zooming in at 150 f5.6. You still get that shallow depth of field you DoF lovers adore!
I wouldn't see myself replacing other lenses if I ever bought it. But it would definitely make a great addition to a professional photographer's gear.