I'm in the same boat and will probably choose CM ATC-210 because of better construction and appearance.
A while ago, there was a long thread in Ars Open Forum about a Lian-Li PC60USB case rattling loudly due to resonance with its fans. While this could, in principle, happen with any aluminium case, it seems to happen more often with Lian-Li cases than with CM cases. In fact no one reported a similar phenomenon with CM cases. While this might be due to the smaller population of CM owners, it may also be due to difference in construction quality. At least, choosing CM seems to be a safer bet in avoiding the resonance problem. Moreover, CM has two fans compared to three fans for Lian-Li.
Although quietness has the highest priority in my decision making regarding my second box, I have also taken into account some aesthetics. No offense to Lian-Li owners, but I'm not so much impressed with Lian-Li's design. On the other hand, I'm really impressed with CM ATC-210's design. I think it's aesthetically on a par with Macs, or perhaps even better. Lian-Li lacks in elegance, compared to ATC-210. But aesthetic evaluation is quite subjective, so others may feel differently.
Costwise, Lian-Li wins obviously, and Lian-Li may be more cost-effective, depending on how one values both. However, to me, getting a rattling, noisy case is something that I'd like to avoid at all cost since it defeats my objective for getting a new case, so the price difference is not of much significance. Moreover, to my eyes, CM has better design and appearance that partially justifies the price gap.