SolidCoin an incremental improvement over Bitcoin. Replacing Bitcoin will require an order-of-magnitude improvement. Non-starter.
It's meant to be a complementary currency and coexist with Bitcoin. Anyway, right now 1 SC is two orders of magnitude cheaper than 1 BTC.
For a currency, there's been a shameful lack of effort to get vendors to adopt it and there's no apparent infrastructure behind it at all. 100% of the effort has been dedicated toward development of the block chain and client. Unfortunately that's only one small piece of the puzzle in getting it accepted as actual currency.