UX problems with base layer payments include:

• Mining fees are sometimes high
• Confirmations usually take several minutes
• Using it privately requires running a coinjoin server

UX problems with lightning payments include:

• Setup fees are sometimes high
• Payments frequently fail
• Payments aren't asynchronous (the recipient has to stand there with their device open waiting to do a revoke_and_ack on their old state -- unless they use a custodian)
• Payments that do succeed occasionally take more than 30 seconds (due to stuck payments, automatic retries, and no ability to say "stop retrying" in any existing wallets that I'm aware of)
• Using it privately requires manual channel management