This is my experience with WINMOR as it presently stands.
With a really good connection to an RMS/PMBO station that supports the wider bandwidth Winmor modes (about 1600 Hz), you can get Pactor
III speeds. I've seen over 5000 bytes/min from my home setup. At present, that is going to be the exception rather than the rule
. There aren't very many wide bandwidth Winmor RMS stations, so the likelihood of finding one that will give you top speeds at your location is not great.
There are more RMS stations providing the narrow (500 Hz) bandwidth mode, and if you are coastal cruising in the USA you will probably, but maybe not always, be able to find a station to connect to. Speeds are likely to be in the 500 to 1000 bytes/minute range (but maybe as high as about 2000 bytes/min) with these stations, so best used for short text emails and small GRIB files.
There are some European WINMOR RMS stations, but I don't know how coverage is over there.
Using WINMOR will take a lot more dabbling and knowledge to make good clean connections than using a Pactor modem
from SCS, so unless you are a bit of a techno-geek you probably won't find it very satisfying.