Cochlear's comparison
Advanced Bionics' comparison
I haven't seen independent comparisons of the latest technologies available yet.
What we looked at when deciding between the products in 2007 and again in 2008: I think there are strong arguments for the technology / functionality of both products, and there's a HUGE amount of marketing chatter to wade through (do more electrodes or pulses really matter if the 'software' isn't utilizing them in a functional way? Is there really more 'music appreciation' if research on subjects doesn't back that up? Does having more or earlier patents matter?).
So, torn between the products on a technology/functionality basis, we looked at the surgical aspect as one deciding factor: our hospital's success rate, our surgeon's experience and found that two of the products were far more familiar to our hospital (from AB and Cochlear) and our surgeon had extensive experience implanting one in particular (Cochlear). At our hospital, there had been several re-implantations required on the AB side due to device failure (although I'm certain that was due to a limited issue that is no longer a problem, so frankly, that didn't impact our decision). Surgeon experience weighed most heavily.
Also important: market penetration. I know this seems superficial, but we wanted to know which company was more firmly established, might be around longer, and had the support base we'd need in the years to come: the market of CI wearers who who need clinic/audi/surgical/product support and expertise. Specifically, we looked at which products were our cochlear clinic's audiologists more familiar with, with which did they have more training? Those mappings are critical, for a very long time. This was close between AB and Cochlear, and although they reported that they had more toddlers getting Cochlear, more teenagers were choosing AB because AB external equipment looked very much cooler and were riding the PC/Mac marketing alignment AB was promoting (this was pre-N5, of course, and I too thought the AB looked a lot more cool!). Li-Li was in diapers, though, so coolness was a lost cause. But streamlining that processor is critical to keeping it on the child's head, so the size/shape/coolness of a processor is nothing to sneeze at. But overall, the market our clinic supports was and is predominantly Cochlear.
So, we chose Cochlear, but it was so close that we considered an AB for the second side a year later, to provide all possible benefits. Surgeon experience and concern that the different strategies employed by the two processors might conflict led us back to Cochlear, though.