BMax GUI uses the OS's native GUI, thus it gives a more standardized, professional feel.
I-Glass uses its own GUI, which is always lacking a feature or two that a user may expect after becoming used to the OS's native GUI, thus feeling less standardized and less professional. However, its more flashy nature makes it ideal for games and fancy things... and its ease of use (actually, ease of use depends soley on your knowledge into the depths of GUIs) may make it worthwile for quick editors with which you don't need to worry about what the end-user thinks.
Thus, like most things, they both exist in their own realms of excellent usefulness.
I-Glass uses its own GUI, which is always lacking a feature or two that a user may expect after becoming used to the OS's native GUI, thus feeling less standardized and less professional. However, its more flashy nature makes it ideal for games and fancy things... and its ease of use (actually, ease of use depends soley on your knowledge into the depths of GUIs) may make it worthwile for quick editors with which you don't need to worry about what the end-user thinks.
Thus, like most things, they both exist in their own realms of excellent usefulness.