The AS-C1 will be cheaper but....
The Bic center channel, with the Ed Frias modification, is supposed to be one of the best center channels around and has a small cult-following. I was thinking about using the Bic CC with my Athena F-2's because they overpowered the C-1 center channel. Others on this board who had this same problem told me they just bumped up the volume on the CC in the Receiver setup and that fixed it. I tried that and sure enough it worked and I felt stupid for not thinking of this simple solution.
The Bic has two 6.5" drivers where as the Athena has two 5.5" drivers.
Are your Mains Athena's? I don't know how matched the timbre would be with Athena mains but since CC are used primarly for voice I would not think it would be that noticable.
Many think the Athena AS-C1 is the weak link in the Audition Series but I think it works fine, once adjusted to match your mains. I was thinking of picking up another C-1 so I could have a medium-room setup with all front three speakers being the same and have been testing the C-1's as front mains. The C-1's can be positioned both ways and some use 5 C-1's for their HT systems. So far I prefer the B-2's and even the B-1's over the C-1's for use as front mains, but my testing is a little skewed because I don't have the C-1's on stands - they are on order and should be in this week. I find that the low-end if fine but something is missing in the highs; can't quite put my finger on it yet. The tweaters are all the same in the Audition series, it must have something to do with it being mounted in between the woofers.