I used
Digitize Home Movies, Photos, Slides & More with Legacybox(R) and they did an outstanding job. Individual media is all barcoded and tracked. They send updates and progress emails regularly. All converted media is returned on a thumb drive - they offer other options as well.
They aren't the cheapest, but they provide an outstanding result and right now, they're having a Valentine's sale with major discounts. Sometimes, the cheapest solution isn't the best, and paying a little more for excellent outcomes is worth it.