I have helped other use both ARA and USGB...all sales went well, and those that I have helped selected by themself as to which one to use.
Everyone would use the one they used again.
I have not used Midwest and have not helped anyone in the past year and a half.
I understand new IRS regulations require anyone buying over $600 in scrap gold from any one person to issue them a W2 form for tax purposes. You might ask when you talk to the buyer. I would suggest you talk personally and not just email. You will have a much better fell that you are dealing with the correct business of your choice.