You need to see what is your business and weather AX supports the business you are in. Some businesses are easily translatable in AX but some are not. You just have to see the product capability and the partners around, as I had a bad experience in AX 2009 and 2012 implementation in my company which was a Poultry farming & breeding company. AX was unable to handle the farming part of the company, which was the major area of the company, so my company was unhappy.
As my company was a group of companies and one of the entity was in Discrete Manufacturing, so AX was implemented in all of the areas easily and that legal entity of the group was happy with AX. So you need to see your business and then the possibility of AX implementation on it and the partner working for you. One more major need of ERP implementation is your own employees wish to shift on an ERP.