Having had both, the Pebble buttons got a bit gummy over time whereas the Pebble Time buttons are still very solid. The latter seem more well put-together, IMO.
The Pebble 2 SE buttons are known to fade off eventually. There's a hardware mod (3D printer) which requires orig. Pebble Classic buttons to fix it. Unfortunately, I broke my Pebble 2 SE in the process. Its very delicate hardware.
I ended up buying a Fossil Hybrid HR instead. Its a decent watch, just a tad expensive.
Yeah, I guess that was one reason for the change…
Absolutely, I have used pebble time round since it came out, no button issues