What are some alternatives?
When comparing Let's Encrypt and Comodo, you can also consider the following products
OpenSSL - OpenSSL is a free and open source software cryptography library that implements both the Secure Sockets Layer (SSL) and the Transport Layer Security (TLS) protocols, which are primarily used to provide secure communications between web browsers and …
Digicert - Encryption & Authentication
FileVault - FileVault is a method of using encryption with volumes on Mac computers.
GlobalSign - GlobalSign offers a range of SSL Certificates with the strongest 2048 bit encryption and value add features to ensure your website is protected.
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
GeoTrust - Guarantee online customer security with SSL certificates from GeoTrust. Purchase in bulk, manage multiple certificates & become your own Certificate Authority.