Is there an alternative full client?
- bitcoind
- Bitcoin-Qt
- Gocoin
Both bitcoind and Bitcoin-Qt are the main backbone of the Bitcoin network. I'm not sure what ratio of nodes are bitcoind or bitcoin-qt.
I would actually say the bitcoind is more important because this is the one all the services would use.
Versions are much more important. Basically, stuff after about 0.7 or so supports the wallets of everyone owning less than a Bitcoin or thereabouts.
Sorry but my english is a little bit rusty. Are you implying that everything above bitcoind 0.7 is not trustworthy?