None.

For individual users, the best solution for storing a large amount of bitcoin is multisig-timelock addresses.

Like BitKey's Solution: https://medium.com/bitkey-blog/bitkey-s-multisig-timelock-address-22ff41c1b017

This has a big advantage over hardware wallets. Users no longer need to worry about coin thieves and key/seed-paper loss disasters.

The hardware wallet can't solve the problem of seed paper backup, and it can never solve the supply chain attack problem.

Must every one “like to have something cheaper than today's btc wallets and hardwares and 99.999% hack-proof?.”
That will be great. Key-management is big problem that block the Bitcoin mass adoption

Sorry, apologize for that.
I just think that everyone should not release their number of  bitcoin holdings. This is common practice. I saw your form collecting this information.

Like a phishing scam, why are you doing this?

I designed a logo for the 10 years anniversary of Bitcoin.
You can switch to this logo in the settings of BitKey app.

https://twitter.com/bitkeyapp/status/1075338931267203072

Recommend BitKey wallet.

BitKey uses a password and some security question to encrypt wallet data.
The password hint and security question will give the family member a good hint to decrypt wallet.

Besides the above design,  BitKey supports multisig-timelock address which is perfect to storage Bitcoins without worry about lost and stolen.

APP:
https://itunes.apple.com/us/app/bitkey-bitcoin-wallet/id898643317?mt=8

TimeLock-Multisig Address
https://medium.com/bitkey-blog/bitkey-s-multisig-timelock-address-22ff41c1b017?source=collection_home---6------0---------------------

Recommend BitKey for iPhone, a Bitcoin wallet since 2014.
BitKey supports 2-of-2 multisig-timelock address and Multi inputs-outputs UTXO level transaction tool.

1. Without airgap, no one can confirm "keys will not leave device". iPhones/iTouch also have the keychain(Secure Element/chip) and application sandbox mechanism, which can also be said: if the iPhone did not break jail and the wallet app did not disclose your keys then no one can touch your private-key on the device(iPhone).

2. Multisig and redeemable address can solve backup "issue". One key is encrypted backed up will never lose, other cold keys with airgap protection. 

3. I still think most people will forget and lose their bitcoins themselves. So for users who are not familiar with tech and neglect data backup, using a soft wallet even a web wallet is not a completely wrong choice.

Hardware wallets(Ledger Nano S) need connecting to PC, the PC is online.
While, I think the bigest problom of hardware wallets is seed-words backup issue. Keys loss is big threat than theft for most of users.

Bitcoin wallet should be a pure keys managment tools without account and log-in issues.
All wallet with account is designed to become a trade exchange, I think.

Recommend the BitKey wallet for iPhone users. BitKey is a pure Bitcoin wallet, like 1 password managing your password, bitkey managing Bitcoin private keys.

Hardware wallets can break down at any time, requiring extra work to maintain.

Best practice to manage large amount coins should be choosing a multi-signature scheme.
For individle users mobile phone and personal computer multi-sig is practicable solution.

Decent mobile Bitcoin wallet is good enough for daily use. Nowadays, the security performance of mobile phones surpasses that of ordinary hardware wallets. iPhone is more secure than a large number of hardware wallets(base on Android).

Agree.


However, I think the main drawbacks of hardware wallets are ignoring the private-keys backup problem. Private-key/secret-word loss is a larger risk than theft.

I think the best Bitcoin wallet practice should be a grass-root solution base on mobile phone platform.
And, with perfect security data backed-up which can resist bruce-force attack.

Then base on the decentralized key management mobile app, there will be third party provide multi signature api which can mix traditional access  control, such as device id, IP address, geographic location, the amount of funds.   

Combine these two aspects, I think this will be the future wallet.

Beside, BitKey wallet find the  NFC-XOR card solution which can take advantage of open cloud storage to back up private-keys and keeping perfect security.(https://bitkey.app/)




 

If you use iPhone, you can use: Bitwallet, Breadwallet, GreenAddrees, Bitkey.
You can search these app on appstore.

This is a soft-hardware hybrid Bitcoin wallet and invents the NFC-XOR card solution this may be an alternative to hardware wallet. https://bitkey.app