I switched from 3C to Grand Prime. It's not an upgrade, other than camera and battery timings.
If you can root phones, remove bloatware and greenify apps, then grand prime will run as fast as 3C, otherwise not, due to 1GB ram.
For stock (non rooted) users, who use multiple social and IM apps, 1GB ram is barely sufficient, as these social and IM thick skinned apps cannot be killed by Androids own LMK (low memory killer) system, in case if the ram gets full and then phone lags.
4C is much better option, rest is your choice.