My understanding is that we will explore all options for Somerville. I can imagine that there are advantages for the different scenarios in different homeowner/biz/condo situations.

For example, here's what Needham had: http://solarizeneedham.org/faq/#Q16
There will be two options for participating in Solarize Needham – you can purchase and therefore own the system or enter into a lease or Power Purchase Agreement. There will be five tiers of pricing, with the savings increasing for everyone as more contracts are signed.

[Note: the Needham project is just an example, some details on things like incentives have changed since theirs.]

Thanks for sharing your experience. That helps me to know about what people might want.