[exim] Canvass popular opinion - AMAVIS(new)

As I continue to build my Exim gateway I've can see the question of a
virus/spam quarantine on the horizon and would like to ask Exim expert
their views.

I'm aware of AMAVIS(new) being a popular choice but it appears to have
two distinct sets of views. There are those that sing its praises, there
are those that scorn it.

My aim with my Exim gateway is to offer a combination of per-domain and
per-user settings as far as virus and spam scanning is concerned and
given the excellent core features that Exim offers in terms of ACL's and
message processing I can't see how Amavis would be particularly useful.
I can see it has a place with less capable MTA's, but Exim appears very
flexible as it is - but perhaps I'm confused?

Can I achieve what Amavis(new) does with Exim without it? I'm happy to
write specific helper scripts (Perl or shell) for tasks that will fit -
but would that be waste of time?

Ideally my 'per user' settings would allow a user to select if they
block(drop at smtp time) || tag(change subject header) || quarantine ||
allow messages that either contain a virus or score above their own
personally set spam score threshold. I can easily hold their 'settings'
in a database against their username and make use of the plethora of
Exim features to do most of this. The sticking point seems to be
management of the quarantine ?

I'm very interested in the views of experience people using Exim in
production and I'm keen not to go the wrong way as I plan for this.