The current issue of Accounting Today shows that all but 14 of the top 50 accounting system VAR's are selling MS Dynamics.
The other sell Sage, SAP, etc.
One caveat.. this survey is aimed at SMB VAR's and excludes VAR's selling to very large companies where SAP, ORACLE etc. would have a larger presence.

The impact of cloud-based accounting, much touted in the press, seems to be minimal, at least for now.

Clearly, MS is doing something right in the SMB market.
Many (including me) doubted whether MS made a good move when buying Great Plains and Navision.
Ballmer seems to have proven us wrong.