I've been using a Nokia 101 Dual SIM for the past year, and previously had a Samsung slide phone (single SIM) that I quite liked, so thought I'd give this one a try, because I need dual SIMs.
It's fine. It does everything the Nokia does except play music files (and I don't use that feature anyway). Of course, in true Samsung tradition, there's no attempt to standardise with the competition, so there's a bit of learning involved to be able to access some features, but that's no real problem.
I quite like the way special characters are accessed when texting, with each character being assigned to a number key in a series of grids, and I also prefer the single (long) key press to unlock the keypad over the Nokia's two-key combination.
The default tones are a bit irritating, but they can be changed/eliminated with a bit of experimentation. As somebody else said, the message and call tones are a bit quiet, and I've missed a couple of calls as a result, but it's possible to crank up the volume, so it's not the end of the world.
All in all, you really can't complain at this price.
EDIT: It's quite instructive to revisit reviews, and see how prices change in a very short time.
I paid about twenty quid for this phone, and it's now being offered for £31.94!