7sus4 chords do not display in the correct font.

In jazzchords.xml, the proper abbreviation is simply 7sus - the 4 is understood. Same story with cchords_muse.xml, which is based on the old jazzchords.xml and is what I think of as its replacement. I set up the "cchords" files to faciliate customization; that's what the initial "c" stands for. So the idea is, you start with the version of "cchords" that comes closest to what you want, and then if you to customize it further, you edit that and save your own version. There are instructions at the top of the "cchords" file that explain the process. It's not pretty, but it works.

As it is, the cchords_rb style uses "sus4" (since it is trying to emulate the "Real Book", which uses this). The rest of the "cchords" files all use "sus" by itself, as that is the more common usage by most other publishers. The "customchords" file you mention is something that eventually formed the basis of the "cchords" files, but the "cchords" version is the official one shipped with MuseScore.

2.0 provides a chord editor window (Style / Chords), but as far as I know, you have to edit each chord id individually, and there are a *lot* of chord id's that use the "sus" abbreviation. I am not sure if there are plans to enhance this, but on my list of things to do is to create a utility that will generate a new chord descriptor file for you, so all you have to do is fill in a dialog where you choose what sort of abreviations you wish to use for major and minor, whether you want to display "4" in your sus chords, etc All the same stuff you can currently edit by hand in the cchords file, but without the need to decipher all that XML. I'm just waiting on, well, I don't know, the right combination of free time along with some sort of clear signal as to the what else has changed or will change in how chords are handled.