I ran another 200 trouble-free rounds of ball ammo through my XDS yesterday. The trigger has really smoothed out during the 500+ round break-in period. The pistol points naturally for me with the large backstrap installed.
Here is a sample target: 17 rounds fired standing off-hand at 21 feet slow fire.
I attribute the slightly low left group to trigger control rather than sight misalignment. That should improve with continued practice and familiarity with the XDS trigger. The group is certainly acceptable for self defense work at self defense distances. The rough texture of the grip surface aids in control of the weapon with a firm grip, but I didn't find it uncomfortable to shoot at all -- nor did I suffer any pain, blisters, bites, etc. while shooting the XDS.
Springfield has a winner in the XDS. If no one buys the extra one I have listed for sale, I won't complain about owning two of them!