Is there a problem with iOS Password Managers?

Some people use password managers on their iphones so that they do not forget what their passwords are but are they really safe? Many of the free password managers have unencrypted main passwords to access the app meaning if you can get to the device then you can easily bypass it to get access to all of your passwords.
What are some of the things that you can do to protect your self?
1. use a passcode on your device.
2. Use a complex passcode.
3. turn on erase data on the iphone so that if it is stolen all of your other info is safe.
4. Dont use password managers. Use passwords that you can remember and no one else can get so that only you have access to the information.