Actually thats not totally true. As long as the cheaper one used correct parts(boy thats a mouthful) all is good and differences can be in finish and profit. But you can buy ones that have bad parts, weak parts, heat treating to thin etc.. that will jam, fail, break etc... Which if you life depends on it or could, not good. If its a plinker no big deal. And you can buy guns for 1800+ that may not work, be accurate and so on. Go with proven names and you'll be fine. Adjust to where the gun fits you and you'll be fine IE if its a lifesaver, cut no corners. If its a target gun, has to be accurate, if its a blaster, then cut all the corners you want and fix any troubles later on.
Jeff