IIRC the main issue with I2P is that it doesn't natively offer access to traditional websites the way Tor does. You can configure your browser to connect to a remote HTTP proxy over I2P and access the web that way, but that requires you to find such a proxy first (preferably several such proxies, each with multiple users, so that your traffic across multiple sessions can't be correlated by using the outproxy IP), and setting it up is a lot more complicated than Tor's method of "download Tor browser, click run".