If the stitch is well designed and well made, the sewn eye should be strong enougth. You can bet that the ropes manufacturers have studied that very closely before releasing it. There's even a big thread on Treebuzz about sewing the eye by hand instead of by a machine.
Now, it's hard to tell if one is stronger, because usually, the rope itself fails under load before the splice does. If done correctly of course.
Beside the sexy side and the bulkyness, I worry about the abuse the splice can stand during the rope's live. The DRT gives a straight pull on it, but not the SRT if the line is directly choked on the TIP or on the trunk for bucking (I do those two a lot). Friction against the bark and working the splice back and forth by the curvature look harder to me on the sewn splice. Maybe I'm mistaking, idk.