I can vouch for Nebula. Just follow their recommendation to not get the 1x service if you want to use the data for medical reasons. The more passes they make, the more accurate the result.
Downside: those files are HUUUUUGE. Have a good reason to do it before pulling one down and trying to work with it.
Downside: those files are HUUUUUGE. Have a good reason to do it before pulling one down and trying to work with it.