I believe the Gen4 FAP speeds have gone up from the 150Kbps they were, but I don't know if they are equal now to the Gen5 FAP speeds. But, with that said, if they are, the official statement on Gen5 FAP speed is "as low as or lower than 1 Mbps."
No ISP that I'm aware of guarantees a fixed speed under all conditions. It is all published as "up to".
All HughesNet has done is align themselves with other ISP's who claim "unlimited" but really mean they don't cut you off entirely. Especially cell providers who are closer to satellite Internet than cable is.
At least HughesNet has enough morals to not call their service unlimited like many others. They have published data plans with data caps which means speed will be reduced after the plan speed is exceeded. What that speed end up being is based on lots of factors including priority to those who have not exceeded their plan allowance.
So, "no hard data caps" basically means your speed will depend on traffic and priority once your plan allowance is exceeded.