Also working through Tait, very happy with my experience with them thus far.
Limited qty's of the new Yamaha F100 expected to arrive in March, almost all already reserved. Looking at the discounted prices of the F70, F100 (current) and F115, you can expect to pay approx 15% more for the new F100 over the Suzuki 90's like for like. Those factors, together with unmatched specs like a 2.59 gear ratio to spin a 14" prop and especially a 16kg saving on the transom, made the Suzuki's the "right choice" for me.
In all honesty and I said this in my original post, I have always favoured Yamaha and I was therefore trying to make the F100 option work. But if you remove brand bias and exclude any local dealership relationships, the Suzuki 90's on paper are the right 4 stroke motor for the 620 Super / Butt cats. That's my opinion. Then you consider the $$$ saving and that everyone raves about the Zukes ... it makes Suzuki a very convincing option.
I will provide feedback in due course. I will be able to give a good comparison as I have a new generation F200 on another boat which I would imagine would operate similarly to the new F100.