I think OP means what is the difference between Force FX and in-hilt LED sabers. If so, the difference are as follows-
Force FX have-
An on/off sound, a couple of clash sounds, and up to 4 different swing sounds.
A "scrolling" effect when the blade activates, simulating how they look in the movies.
Light is provided by a string of LED's running up the blade-this provides the scroll effect. However this also means they are quite brittle and prone to damage if used for dueling.
Movie accurate hilts.
Powered by AAA or AA batteries.
Custom sabers have-
In hilt LEDs. This means there are no brittle strings to be damaged, and as such they can be used for quite heavy dueling.
No scroll effect-blade turns on or off.
Option to come with or without sound. No sound means the saber is substantially less expensive.
Many options of hilt style. Some based on movies, others are not.
Option of different sound cards for different effects. Many tiers of price are catered for,some with very extensive and customisable sound fonts.
Option of different types of batteries.