The INT-150 is based on the X.5 series rather than the XA.5 series, so it presumably gives something up to the XA's in refinement in exchange for the extra power.
The INT-30A is more directly comparable, being basically an XA30.5 with a passive volume control and control circuits.
The INT-30A is more directly comparable, being basically an XA30.5 with a passive volume control and control circuits.