Hi there
You can use non-Types fields in Toolset, outputting them in templates with the wpv-post-field Views shortcode, for example, or even using them in filters for Views, and you can publish posts including non-Types fields with Toolset Forms (using generic fields).
That includes ACF custom fields, with a major proviso. You can only handle simple such fields, stored as plain text. Types stores some fields in a proprietary format, as does ACF, and Toolset doesn't know how to handle complex ACF fields, which won't work.
So if you were only thinking of using simple ACF fields there should be no reason not to, but if you were only thinking of using simple ACF fields there would probably be no reason not to use Types instead.
ACF is a very good product and there are some features where it is better than Types—the UI for adding options to select fields is much simpler, for example—but because of the convenience of using Types with the rest of Toolset you would need a very good reason, I think, to choose ACF over Types.
Are there some specific features of ACF that you require that are missing from Types? (Bear in mind that Types is getting a big lift in terms of features with the upcoming Types 3.0 that you can try now in beta.)
Toolset already has a compatibility layer with Beaver Builder, and so you can, for example, create templates with Toolset and design them in Beaver Builder.
That is currently missing with Elementor. We are cooperating with Elementor to add better support for Toolset but we are not there yet, so it might not make sense for a new project you need to work on now.
So the key question about ACF is whether there is a specific feature that is missing from Types? It may be possible with a little extra coding or some kind of workaround.
