Compared to other encryption software for Windows, BitLocker is the most reliable one because it is developed and maintained by Microsoft, an economically strong company with a good security track record in recent years. Unlike open-source encryption software, you can expect Microsoft's ongoing functionality and security updates for BitLocker.
BitLocker encrypts the entire hard drive, not just specific files. This fundamentally differentiates it from most other file-level encryption software, e.g., Gilisoft File Lock Pro, Folder Lock, and Wise Folder Hider. It is designed to protect the disk as a whole rather than a subset of files on the disk.
Many third-party encryption apps are not able to encrypt the boot partition ( C: drive ) on Windows while BitLocker is capable of doing this. BitLocker encryption is also integrated with Windows Secure Boot to prevent the core OS files from being tampered with.
Microsoft BitLocker also has some disadvantages:
1. It is only available on Windows except for Windows 10 Home edition, Windows 8 Home edition, Windows 7 Home edition, and Windows 7 Professional. If you want to enable BitLocker in Windows 11/10/8/7 Home edition and Windows 7 Professional edition, you can use M3 BitLocker Loader for Windows to help you.
2. BitLocker does not allow the user to choose an algorithm by themselves. It uses the very strong AES algorithm but defaults to 128-bit keys rather than the stronger 256-bit keys. However, other programs allow using 128-bit AES encryption or 256-bit AES encryption as the defaulted encryption algorithm according to the user's needs.
3. BitLocker does not support the 'Plausible Deniability' function. 'Plausible Deniability' is an interesting feature. This feature allows the user to set two passwords. One is the real password that fully unlocks the drive. The other unlocks a separate partition that contains less sensitive files. If someone is forcing you to unlock the drive, you can enter the second password and the attacker will see that you have unlocked the drive. There is no way for the attacker to know that this feature is enabled, even using advanced forensic techniques. VeraCrypt provides this interesting function, you can download it to have a try.
To sum up, If you are using Windows, I highly recommend enabling BitLocker with 256-bit AES. It has almost no big drawbacks and protects against important attack scenarios. Just be aware of what it does and does not do.
If you're using a Mac, you can use FileVault to encrypt the whole disk to protect your data.