- long battery life (2-7 days depending on model)
- e-ink colour screens, that were always on
- an extensive app/watchface ecosystem
- actual attractive watches
I had a series of them and was all-in on the new models announced via kickstarter, when they suddenly disappeared and were bought by Fitbit. All forthcoming products were killed off.
They've been pretty reasonable with sunsetting the servers and helping the community move towards an open model, but it's only a matter of time before my Pebble Time Round bites the dust and I can't fix it (my partner's has already gone)