How much does one give up in getting the 35-90 as opposed to the primes?
The obvious is that you can't quite get to 100mm, but the most significant (IMO) is the 5.6 aperture at 90mm with the zoom versus 2.2 with the 100mm prime. Despite only 10mm difference, many folks elect to have both of these lenses and find that they don't overlap in function.
have to agree with the above post re:100mm prime.
My first Hassy Lens was the 35-90mm and had no need to use primes until I got the 100mm and 150mm
the zoom is suitable for all the work I do. I would like to try the 80mm at some stage, but never have the requirement for it at this stage. The 35-90 is seriously one great addition to my quiver.