Very nice, although it might have been cheaper to buy a chain tool once you factor in the time you spent on it, you've now got one that's unique! I think it also looks kind of cool, but that's just me...

My only criticism is that it might be a bit hard to keep the chain link centred in the tool, since it hasn't got the baffle plates like most commercial chain tools do, but the chain tool on my multi-tool doesn't have them either, and with a bit of careful use, that's worked fine for me whenever I've needed it.