The proprietary development tools that many of the ERP vendors – even the traditional ones – effectively limits the customization capabilities on which the success of the ERP implementation project depends.

Also, finding developers that have a good expertise is very difficult and expensive and most of the times, even impossible.

Moreover, the learning curve for these proprietary development tools is long and most of the times, the help provided is not quite as good or available than the one for the common development tools provided by Microsoft.

I can say that I chose Acumatica for that exact reason: not only I can use the latest .NET development tools from Microsoft – that I already know and is taught at school – to customize the software but I also have access to the source code of the application.