The unit with the best price-to-performance ratio.

To be honest, I didn't understand how 8 bears could only kill two birds... In TC3, they killed more golden or black dragons... Oh well...

I'll answer. It's just that in TC3, heroes don't have 0-0 stats, but 10-10. This significantly elevates the bear above other level 7 monsters. But even so, they would still leave 7 phoenixes alive. If the stats were 50-50, the bears would easily win :)