Anyone looking for a slightly cheaper alternative, check out the tamron 70-180 f2.8
Sigma have just brought out their 28-70mm f2.8. It's smaller and lighter then the tamron. Also has af/mf switch on it. Slightly more expensive then tamron, but nice lens.
I do like an almost-all-purpose zoom when just travelling around. The Tamron 28-70 f2.8 is my default lens. I hate faffing around changing lenses and missing a shot. I rarely use my primes or my crappy 24-240, but they definitely have a place in my kit bag. Wish I could justify the spend on something better than my 24-240
I wanted this lens but a lot of people who own this lens have said they want an upgrade as well as the 85mm 1.4GM. I’ll hold out for now as Sony seems to be going in the right direction with IQ and weight
A lot of photographers don't like using primes. They prefer zooms as they have a good range without having to change lenses and less running around involved. I personally use primes, but I have friends who like using zooms as thats what they are happy with out of habit and style etc.