Plex Online is one of the stronger all-around competitors in the mid-tier manufacturing ERP segment. 

You can find a pretty long list in the manufacturing section of our Product Finder, and just select the "Mid-Size Business" box.

Rootstock should always be considered - a complete, comprehensive ERP system delivered as SaaS.

CenterPoint Accounting Software works great for medium-sized manufacturers. Features such as assemblies ("kitting"), bill of materials, multiple units of measure (purchase and sell), strong inventory management, order entry and purchase order, and more are included. CenterPoint also has a strong financial back end, and unlimited data capacity, so the system does not get bogged down by too many items/orders, etc. Customizable reporting is also included, so you can create and save your reports the way you want them to be. To learn more visit http://www.redwingsoftware.com/accounting.