I'm taking Amtrak for the first time on a Friday morning from LA to San Diego in the AM, returning San Diego to LA Sunday around 1 pm.

Should I take Business Class or Coach? I'm conflicted. I want a pleasant ride, but also don't want to pay for the upgrade if the difference is not very significant in terms of quality, comfort, and noise level.

What would compel me to pay for the upgrade is if this is a heavily traveled route, and Coach would involve being packed in with sardines, with lots of noise, and potentially having to stand for a portion.

Is this a heavily traveled route, such that there will be lots of noise and people during the trip?

If traveling by Coach, what degree of likelihood is there that I wouldn't be able to get a seat?

Curious for feedback on this, especially if you have traveled this route and or have useful feedback.

Thanks.