Well, lemme see.
I have crossed the Gulfstream 30 times in the last 4 years.
Yes, it can be hard or it can be easy....
Many a times ya wanne sit and wait for the weather
If it is blowing more than 15 from the North or the NorthEast, you don't want to cross.
Since the stream runs South to North, any North wind
component wil go against the current
and kick up a rather lumpy chop.
20 from the East or SouthEast is another homemade limit from crossing to the East.
Ya rarely have Westerly winds, only for a few hours after a front have just passed.
In the winter ya have strong NorthEast winds, in the summer SouthEast....As a general rule
Whenever I need to sail to the South, then the wind
is from the South..When I need to sail to the East, the wind is from the East., so there is exceptions to the rule
A good place to wait for weather
is No-Name Harbour in Key Biscayne, it is nicely protected in the winter, but too many bugs there in the summer.
So to sum it up, yes, the stream can be lumpy at times, check the weather and start early in the morning when the winds are still light....