All three I mentioned, once installed, provide you with a fieldtype that would give you the ability to associate multiple images with an entry through that single field. Actually there’s a fourth one - Channel Files - but Channel Images is much more specific to IMAGES so it’s likely the better alternative of those two.
Matrix is the one of those options that really is just a recalibration of native functionality, in a way. It takes a single field and breaks it up into a series of fields. You define the columns - each column being a fieldtype. So for multiple images being associated with an entry, for example, you might have columns like Image, Caption and Alt Text. For each of these columns, you specify a fieldtype - and so the EE native file field can easily be the one you use for image. Caption can be text with multiline checked (same idea as textarea), for example. And so on the entry screen, you just add a row to the matrix field for each image you want within that entry.
Beyond its usage in your gallery is where you really wind up benefiting, potentially. While Assets and Channel Images are fantastic for handling files, Matrix can handle files, but also data. So if you have a staff list for example, and for each staff person you want to display one or more phone numbers for each (a silly example, but you’ll get the idea) - within a single field, you can provide the content editor with the ability to quickly and flexibly enter 4 phone numbers for one staff person, 2 for another, etc. with the simple flexibility of the rows in the matrix field. And there are a variety of fieldtypes that are supported by Matrix, including many other third party developer’s add-ons. And Matrix is supported by a few other third party add-ons, including Low Variables, for example.
So for me, Matrix is the most flexible option because I tend to apply it to tasks outside just images. It just comes down to whether you envision needing that same kind of flexibility outside of your images. If not, one of the dedicated image management modules like Channel Images or Matrix, offer you a bit more horsepower and a broader feature set for sure.
Hope that helps.