I use an Accu-Chek. It is great, and seems accurate. It has an integrated blood lancet device - which takes cassettes of 6 test lancets. My meter takes cartridges of 50 test capability. I have some points that are worth airing.
The meter plays up sometimes - and give funny messages. I have found that in those cases I set to changes the cassette, and reload it. All results are maintained, and the meter goes to the right place in the cassette.
The meter can sometimes accept the blood sample, and times away, but comes up with an error message indicating insufficient blood. Irritating. Usually the case when my blood is very low.
There is no calibration liquid.
For its faults I find the device great. It frees me from messy bloody strips, and the prick cartridge saves me from loads of sharps.However I do wonder why other manufacturers badger me with meters which only take individual prewrapped test strips. I also wonder why my test strip cartridge is only 50 tests, why can't this be increased to 100 or more? Similarly, why the pricker device is only 6 pricks - many more would be really useful.
It is a great unit.