There's also the ReliOn Ultima - which is/was manufactured by a different company than the Confirm/Micro. I used the Ultima from last January until about May. Got really frustrated as it would give me readings that were not logical, I'd take another test and would get as much as 150 points different. It also required a LOT more blood, and since my guy doesn't like to give it up, we changed to an Accu Chek Aviva.
I have used the ReliOn Confirm as well as the Bayer Contour in a side-by-side testing for DCIN in January. You can see the consistency in the results on my spreadsheet. I would feel comfortable using any one of these.
It's not that every meter is going to be exact to every other meter - when you use one consistently, you see the patterns and trends your cat follows. That is what we look at mostly. However, please note, on lower numbers, both the Confirm and Contour read lower than my ACA. Some people choose them to be able to stay on top of a hypo before it comes on - which makes a LOT of sense!
I've not used the Prime, so can't offer any info on that.