Also, zcash has the trusted setup issue, which requires that you trust the developers were not compromised or did not store data during the setup, or they might be able to print infinite coins without detection if the data were to be recovered. For some, this makes it a non-starter, despite the efficiency of SNARKS over Bulletproofs which Monero now uses.
Don't let that deter you though. Zooko only pays himself a $300,000/mo salary. He will struggle to get by without the crowds of new adopters.
There is no "default" behavior. The software gives you the choice between shielded and unshielded, and the enduser has to choose. There is no default.
«requires that you trust the developers»
Not really. In the latest Powers of Tau ceremony, there were 87 participants. This group spans more than just the developers. Even if 86 participants were malicious or compromised, as long as there is at least 1 honest participant, the system can be trusted.
«Zooko only pays himself a $300,000/mo»
Not sure why this is a problem. By comparison, Satoshi "paid himself" (mined) 1M BTC =~ $6 billion dollars. I'm fine with the founders of world-changing cryptocurrencies being handsomely rewarded.
No, Zcash offers the option to always use shielded transactions, if that's what you want. The choice to use a shielded or unshielded transaction rests solely in the hands of the user.
It is true that CPU and memory complexity use to be high for shielded transactions. However Sapling just activated (https://z.cash/blog/sapling-activation-complete/) and it resolves the issue: a shielded transaction used to take up to minutes of CPU time and 3GB+ of RAM, but now can be done in 1 second with ~40MB: https://medium.com/@EthAdvisor/everything-you-need-to-know-a...
Furthermore, Zcash promotes the use of TOR if users wish to hide their IP address.