1) The protocol itself is pretty well vetted, and obviously open for all to spot such issues. As far as the general public who don't know too much about that stuff, I'd say most are still skeptical. 2) There are a ton of different 'alt'-coins, but most of them don't offer much improvement/difference from the BTC protocol. You can check https://en.bitcoin.it/wiki/List_of_alternative_cryptocurrenc... to see the differences