Analyzing the data obtained on our tests, the first conclusion is that the SSDNow UV400 120 GiB does not suffer from the same problem of performace drop with uncompressible data we found on the V300 model. So, the UV400 is faster than the V300 on most writing operations with uncompressible data.
Another interesting point is that the SSDNow UV400, unlike the other two tested SSDs, used a RAM chip as a buffer, which explains the better performance on the 4 kiB blocks with queue depth of 32, which typically benefits from this feature.
Compared to the SanDisk SSD PLUS 120 GiB, we can say the Kingston SSDNow UV400 120 GiB was on average a little faster, performing better on some tests.
So, we believe the SSDNow UV400 120 GiB is a good choice for the home user that is looking for an inexpensive SSD to use as a boot drive for a desktop or laptop. However, because of its technical characteristics, it is not recommended on applications where there is a lot of writing operations everyday, where you need to choose a most expensive drive. Besides that, even performing decently for the home user, do not expect the same performance of a high-end SSD.