That's too bad to hear about the N85. Unfortunately, I would be surprised if the N86 is any better. It doesn't seem like Nokia has really attempted to make any advances or changes in the way they deal with microphone gain and noise cancellation on their phones in years.
I've found Nokia can be very hit or miss. Some of their phones are quite good at not over-amplifying background noise, in particular flip phones, as I mentioned. Although, beware, because at least one Nokia design, the 6133, puts the microphone in the hinge, forcing the gain on the microphone to be turned way up and making for horrible results. But sadly even their high end slider and candybar phones, like the original N95 and N73, which I tested at the Nokia store (a pretty noisy place), suffer from this microphone problem. I would have hoped that in the intervening couple years between the original N95 and the N85, Nokia would have addressed this issue.
I've read that Sony-Ericsson phones are better in general, with this problem, but I can't verify this since I haven't had a Sony-Ericsson phone in years. I will say that all of my subsequent, newer, more high end Nokia phones do not perform better on background noise, than my super old Ericsson T28z. I guess when cell phones were in their infancy, people still cared about how they actually worked as a phone. At some point it seems like cell phones came to be preceived as "good enough" and this issue was dropped (although of course, some bluetooth headsets are still trying to work on the problem of background noise).