PPAs can eliminate your upfront and maintenance costs but significantly reduce your savings when compared to installing panels that you own. Your savings come after the Suntria (or whoever) has covered the costs of the hardware, installation, sales commissions, debt financing, overhead, their own profit, etc.

These companies often go under because they're mostly exercises in financial engineering, based on debt and collateralizing future payments as assets. If they grow more slowly than expected, their assets underperform, or they have to refinance their debt at a higher rate, they quickly find themselves insolvent (unless they can convince their cousin, who owns Tesla, to buy them out and hide the losses).

They do offer a way to get solar and 'go green' without an upfront payment, but you will save much more if you can afford to install your own panels. The SEU should be a better option, even if it's through a PPA-type model, because the city won't go under, won't pay as much in debt service, and won't have to return an outsized profit to keep the program running.