Most of the stories we hear go the same way.
"Your power bill will basically disappear."
Then the power bills kept coming. Now there's a solar payment on top of them.
Then the company stopped answering.
The installer closed, went bankrupt, or just went quiet. The warranty went with them. The loan didn't.
And then the payment went up.
Many solar loans assume you'll put a tax credit toward the balance by a set month. If that doesn't happen, the payment can be recalculated and jump.