The 5-103166-2: The right-angle through-hole mounting puts the pins perpendicular to the board, which keeps the cable routing low and saves z-height in a shallow enclosure.
Gold mating finish and detent lock for vibration duty
The detent lock gives a positive snap when mated — you should hear it click — and resists the connector backing out under shock or cable strain.
3 A current ceiling and wide temperature range
The solder posts are tin-plated (100.0 µinch) for reliable solder joint wetting, with a post length of 0.135" (3.43 mm) for standard through-hole board thickness.
Peer comparison: 1-1871673-2 vs 5-103166-2
The 1-1871673-2 also includes a board lock feature for additional SMT reflow retention, which the 5-103166-2 does not have.