The LTE version has a ceramic back, I.e. the part that rests on the wrist that houses the heart rate sensors. I’ve owned now watched with the composite back and the ceramic.
Although the composite back worked fine for me, now that I have a ceramic back I can see the different.
Difference 1:
The composite back scratched over time with small scratches, the ceramic back is more resistant to these scratched. Oh btw these scratches were caused by the charging puck.
Difference 2:
The composite back felt stickier, tackier? When I would work out, it’s lile it grips the skin better, felt a little uncomfortable at times. The ceramic back glides over the skin easier, doesn’t cause a pulling sensation when watch moves during workout.
Difference 3:
To me, the ceramic back looks better, it’s shined and has a higher end look to it. The heart rate sensors also have metal rings around the sensor that add to said “higher end look”.
Photos:
S0 sport watch with composite back (Left)
S3 LTE With ceramic back (right)