I've had a Galaxy Ace Plus smartphone (Android) for several months now and it's great, but there are occasions when I want something smaller, cheaper and simpler with me, so I still have my Alcatel clamshell for that.
It cost £3 from Argos (last year's model clearout sale) about 6 years ago, easy to use, totally reliable and the battery usually lasts a week.
Provided the information is on the SIM card not the phone I get all the stored numbers on it when I move the SIM card, and SMS messages as well. Definitely worth having both available.