I used to support MultiMate in the late 1980s. I didn't like it much myself, nor use it from choice, but it had one compelling advantage in the timeframe of my first job (1988-1990 or so): there was a network version. This ran off a server share and understood networking.
Not a biggie today, but it was then. Not only could it happily load and save files from shared drives, it didn't collapse in a heap when a user tried to open a file someone else was using. It didn't need a local installation on each individual DOS workstation (IIRC) and it happily printed to network printer queues.
I think it was also significantly cheaper to buy a network 5-user copy than 5 standalone copies! :¬)
Pros: well, not a lot apart from that. Fairly awkward UI even for the 1980s. I believe MultiMate started off trying to vaguely resemble some proprietary minicomputer WP. [*Goes and checks*] Ah, yes, Wang. It kinda sorta emulated a Wang hardware wordprocessor, in the same way that IBM DisplayWrite kinda sorta emulated an IBM DisplayWriter, IBM's dedicated WP.
Its UI was mostly menu driven, but big clunky full-screen menus for file management, plus the weird control keys in editing mode that were absolutely normal for DOS apps. Every app had its own control keys and none of them matched up - even 2 apps from the same software company would often have totally different control keys. MultiMate was no worse than anything else.
Its printer support was legendarily poor, its import/export functions were poor, it didn't support graphics at all, but nothing exceptionally bad for the mid-1980s. It had good mailmerge support built-in, that was quite special for the time; this was often an optional extra. And it could mail-merge stuff across a network, which was snazzy then. I think it even supported a few external (non-MultiMate) file formats for the data source - Ashton-Tate bought it, the dBase people, so I think it could mailmerge in from a networked dBase III database. Very big deal in the mid-80s, something like that. Apps were closed boxes then - you did not routinely move data from one to another. In the early DOS era, dBase III was the database.
MultiMate was already clunky by '88 but it did the job.
MultiMate's great failing is that it came from the era of daisywheel printers and the like. This means /fixed-space fonts/. It worked OK on early dot-matrix and laser printers, but only in monospaced mode with monospaced fonts. It could not cope well at all with proportional fonts and it didn't really understand the notion of different sizes of fonts. There were tons of printer drivers for it - not as many as for Wordperfect, no, but /nothing/ had as many as Wordperfect.
So by around '89-'90, when everyone was going over to proportional fonts on their LaserJet IIs and so on, it started to be a bit embarrassing - you could tell at a glance that MM documents came off something that didn't handle proportional spacing. If you turned it on, MM lost its ability to centre, right-justify or full-justify (AFAICR).
So it fairly quickly faded away.
WordStar was a previous generation of app, really. It came from the CP/M era and it didn't really understand fancy new-fangled concepts like "fonts" or "subdirectories". :¬)
The mid-1980s DOS-era rivals - at least in the UK - were MultiMate, DisplayWrite, and then second-stringers such as Samna Executive. WordStar was still hanging on as a whole family - WordStar 3, then NewWord, then NewWord merging with and becoming WordStar 4, plus WordStar 2000 and WordStar Express. All had totally different UIs and different file formats and so on. Insane, just completely insane.
Then, once they got a bit more mature, two early-DOS-days new contestants rose up: Wordperfect and Microsoft Word. The first usable version of WP was 4.2. It was horrible - everything was combinations of function keys: Shift-F3, Ctrl-F8, Alt-Shift-F5, F4; I kid you not, that might be a typical command sequence - but it was very powerful.
MS Word was weird, for the DOS days. It worked a bit like a Windows WP does - rather than doing [bold on]type[bold off], you typed, then selected the word, then applied "bold" to it. This was arcane in the DOS era, but I liked it. The actual UI was a 2-level menu at the bottom of the screen, with commands like Esc-T-L to open a file: Esc to activate the menu bar, then the Transfer submenu, then Load.
Then the Mac & later Windows 2 started to catch on a bit and everyone wanted pull-down menu bars like the trendy new GUIs. So Word 5 ditched its whole UI and went to pull-downs: File, Edit, View, Format, Tools, Help. Stuff actually vaguely familiar today. Bit of a wrench but it worked.
WP just added drop-downs as well as all the function keys. The WP users hated it - Guy Kewney, a noted UK IT journo and later my friend, before his untimely death, put it like this:
"WordPerfect 4.2 was a bicycle. A great bicycle. Everyone agreed it was a great bicycle, just about the best. So what Wordperfect did was, they put together a committee, looked and the market, and said: 'what we'll do is, we'll put 11 more wheels on it.'"
(Or something like that.)
But despite this, WP 5 really caught on. The bugfixed version 5.1, was huge and became the classic version. It obliterated Word in the market.
But basically, WordPerfect (and to a much lesser extent MS Word) outcompeted MultiMate completely because they were newer enough to natively understand proportional fonts and even resizable fonts. They could do all the fancy stuff (for the '80s) - left justify, right justify, full justify, centre, in a mixture of fonts and font sizes, mixing monospace and proportional, reading the printer's capabilities from the driver and showing you what fonts you had on offer and letting you choose freely and arbitrarily enlarge stuff and so on.
MultiMate couldn't hack that sort of stuff. You set a font at the start of your document and that was it, pretty much, unless you got clever. So by the late '80s when everyone had a printer that could do at least small, standard and large text, super and subscript, a serif and sans-serif typeface, even if nothing more than than, then Word and WordPerfect could handle it just fine... but if you used MultiMate or WordStar or DisplayWrite or anything, you were in for a world of pain.
So they died out quite quickly.
Then came Windows 3 and it all changed.
Wikipedia's article on MultiMate is not too bad.
There's a Spanish version on VetusWare if you want to play and habla un poco de español. Given that Ashton-Tate is long dead, I think it counts as very abandonware!
If you want to try a DOS WP then Microsoft made Word 5.5 freely-downloadable as a Y2K fix: it's on www.microsoft.com somewhere. Google will find it more easily than Bing.