It's not single big attachments, more multiples of small ones (jpg, pdf), we normally have to view the whole doc to extract the relevant data (e.g. a 3 page purchase order may only have a single data line). I guess the other worry with using a hosted service is what happens when you lose connectivity, hopefully our dual WAN setup should mitigate this but there's always the risk that someone digging up the road cuts through all your telco cables (we've had it happen in the past). I'm giving myself a headache here.

I spoke to Open-Exchange before we went for Scalix, at the time they had a single UK reseller who had a single tech trained on it, but at least they were honest about it. Each of our Scalix resellers (3 of them) has assured us they have numerous trained techs on board, but it's always the same guy that answers all my support calls...

I don't know, Exchange just looks like the lowest risk solution.