For MAC users I think that they need to use Quickbooks online.
I didn't think that MYOB was supported in the UK anymore. Isn't this now predominantly an Australian product?
That aside any of the cloud offerings should work for you as they are not dependant on the operating system of yours or your clients machine but rather use the internet interface such as Internet Explorer or Firefox.
Hope that this helps for starters,
kind regards,
Shaun.
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Shaun
Responses are not meant as a substitute for professional advice. Answers are intended as outline only the advice of a qualified professional with access to all relevant information should be sought before acting on any response given.
@A Yes if you're considering an online solution we've definitely built Xero with Macs in mind http://www.xero.com/mac-accounting/ We can offer simple inventory movement/tracking or offer add-ons from partners if you want something more complex http://www.xero.com/advisors/solutions/inventory/
Happy to answer any questions about Xero - good luck in your search!