Hi Sarah, great post!
Just want to bring your attention to the fact that for international money transfers, you need to consider both the fees and the margin the provider takes on the exchange rate, which can account for more than half of the cost.
TransferWise is one of the exceptions as you indicate because they use the mid-market rate, but their fees can sometimes be quite high when you transfer higher amounts of money.
Because we struggled ourselves to find which provider was the cheapest for our transfers, we built a comparison website to compare fees & exchange rates in real-time (we compare more than 350 providers).
You can check-it out here : www.monito.com