Unitronix has been supplying and supporting boards and systems to military systems integrators for 34 years. All of the products we supply are sourced from the best in field suppliers for these types of product and all have many years of history in this area. You can "chance it" and try to use some cheap kit with questionable support in your application hoping that it works and does not flake out at a critical moment, or you can do it properly and get the high level through life support and service required to de-risk your program and ensure the full serviceable life cycle of your system.
A simple equation applies, buy cheap on the front and pay lots more later when it screws up, or get the right kit first up and have manageable support all the way through 5, 10, 15 to 20 years.
When you look into whole life cost for your deployed system do you really want to chance it to the cheap guys, with embedded systems you get what you pay for, cheap in one box almost always means more is spent in other boxes of the XL spreadsheet of total costings for a deployed system.
So if you want to do it properly right from the start give us a call and tell us what you need.