Best block-explorer API? Which APIs support checking bip32 xpub balance?

[HeadsOrTails]

BCI has functionality allowing one yo search an xpub for bip32, and check balances of address: https://blockchain.info/xpub/xpub6CUGRUonZSQ4TWtTMmzXdrXDtypWKiKrhko4egpiMZbpiaQL2jkwSB1icqYh2cfDfVxdx4df189oLKnC5fSwqPfgyP3hooxujYzAu3fDVmz

Is there a RESTful API which returns raw data (for Python)?

While we're on the subject: what are the best APIs for Bitcoin, nowadays?

I find Blockr to be the best, whilst webbtc is quite useful. APIs which handle testnet are preferred.