What is the difference between the EXIF tags CreateDate, CreationDate, etc.?

When using exiftool to analyze some videos that I have, I noticed many date tags inherent to the creation of the video itself (so not dates like the last access or modification dates). Namely, here are the ones I found:

Create Date (CreateDate)
Track Create Date (TrackCreateDate)
Media Create Date (MediaCreateDate)
CreationDate (CreationDate)

The first three seem to be the exact same, whereas the last one seem to include the time zone as well after the date and time (for example, 2017:06:22 16:36:20+01:00).

What are the differences between all of these? Which one is the most "reliable" one to use if I want to rename the files according to the date/time they were captured?

One minor nitpick, these tags are not EXIF tags, they are Quicktime tags (all EXIF is Metadata, but not all Metadata is EXIF). You can add -G1 to your command to see the group they belong too. Additionally, if you add -a to your command, you will probably see that TrackCreateDate and MediaCreateDate are duplicated, one for each track in the file (video, audio, etc).

CreateDate is probably the most accurate, but if the video is coming directly from a digital camera of some sort, it is probably the same value as TrackCreateDate and MediaCreateDate.

Video metadata isn't my expertise, but I would guess that Track/MediaCreateDate leaves open the possibility of keeping track of an earlier created video/sound track and muxing them together for a final product. Something that might pop up if your editing various video clips together.

One thing to take note of is that these three tags are supposed to be recorded in UTC time. See fourth paragraph on the Exiftool Quicktime tag page. The trouble is that some cameras do not adhere to the specs, so the time that appears in the above tags may not at first seem to be the correct time.

CreationDate is obviously different. It includes a timezone, is supposed to be set to the local time where the video was taken, and is part of the QuickTime Keys Tags. It requires exiftool ver 11.39+ to edit. Also of note is that Apple Photos will display wildly inaccurate time if the Quicktime:CreationDate or Quicktime:DateTimeOriginal tags do not include a time zone. Exiftool ver 12.13+ will automatically add the local time zone if one is not included when writing.