Here's my experience. It's not exactly the same, but it's worth a read.
Currently I have a very basic Nokia model. There is a process called 'handing over' or 'hand shake' that happens when you move from one cell (a small region of an entire area) to another or when one cellphone tower 'hands over' the signal to another tower. This process is handled exceptionally well on most smartphones, but not so well on the basic phones such as lower-end Nokias.
So, if you were in the middle of a call and this handshake happens (mostly when you are traveling) and if it isn't done on time, or if it isn't done right, the call is dropped.
Previously I had a HTC Desire S, which I dropped from the top of a building by mistake and hence I ended up with this Nokia. Now, this Nokia had frequent call drops and it won't even notify me when it happens. It got irritating after a point, because I would still keep talking assuming the other person is still listening (while on a call) only to realize that I would have to repeat whatever I just said.
One day, I got so angry, because it was an important call, I just thrashed the phone on to the ground on purpose. Luckily, only the display broke, but the phone would still function normally.
Here's my experience with this phone:
1) Previously, on my HTC, all my 2000+ contact would be synced from my google account automatically. There was zero effort needed on my part, so, basically I had everyone's number on my phone synced automagically - My family, Friends on Facebook, Friends on whtasapp, etc.
With this nokia phone, I would have to manually save each number to the phone (which has only a max. of 500 contacts) also it's a tedious process, because I'd need to type them manually. Since the display is gone now, I need to memorize the numbers of important people. And I could feel in a week's time, my ability to memorize (which was previously rusty) has actually improved. With a smartphone, I didn't have to memorize anything - While convenient, it's dangerous, sometimes. For example, I once needed to recall someone's number to deliver my movie tickets at a particular place and I had actually forgotten their number. It was a nightmare.
And it's not just numbers, I actually have the workflow memorized too - To access phonebook, press right right select. To access recent calls - down down left. Stuff liek that. It's ugly, but it gets the job done.
2) Productivity. I'm a heavy Facebook user. Or I was, rather. I realized, my smartphone alone was responsible for over 80% of the status updates and photos uploaded to my account. It was a content producer by itself. Now that it is no more, I feel the urge to use the platform has considerably decreased, because I don't have a camera phone now and I haven't uploaded anything much since my phone broke.
3) Savings. I saved a LOT. No data plans meant cheaper monthly rates and no phone book meant memorizing only important people's numbers and calling fewer people. I do have a back up of my contacts on my google account though.
4) Safety. I don't walk on the streets typing some random shit on my Android qwerty keyboard nor do I talk to someone over the bluetooth headset while driving. This is subjective, though - Not everyone does all this with their smartphones.
5) No screening. Since my phone doesn't have a display, I wouldn't be able to see who's calling me. If I miss them, I will never get to know who had called me either. So, sometimes, if the phone rings, I just answer and say 'hello' and talk to whoever it is, instead of ignoring people by their name (sometimes to avoid them on purpose, because I would be busy with something). I realized how much I missed out by categorizing certain people as boring. Again, this is a subjective thing.
6) Battery. This phone lasts for almost 2 weeks. My HTC would last only a little less than a day. It's a huge difference. No charging or low battery woes.
All in all, I'm a productive person, comparatively and a more real-world friendly guy - instead of taking pictures of pancakes and uploading them to instagram, I just fucking eat them.