i believe the limit on movement is ~8-10 knots..
the portable dish is suffiicient for most...sailboats.
(if you have a
fast
boat...and the
budget..i'd opt for the high performance)
regular disk you can expect 50-200 Mbps downstream....the flat in motion dish should deliver up to 350Mbps .. uploads are equally poor with 1-20Mbos expectations..
(if you need faster uploads.. you will be explorind dual rigs/bandwidth bonding)
speeds are more depending on "priority" of your plan(the Roam/RV are at the bottom) and how many other starlink customers are around you.
the benefit of the in motion is more its enhanced field of view...its able to
monitor more satellites