SCTY often uses Chinese made panels, which are indeed less expensive than SPWR modules. But, as SCTY is the owner, and you get to use the power...do you care? Really? Do you care if your power company uses Siemens or GE generators? If the panels don't perform its SCTY's reputation and money on the line--and it really is money to them, as they do have to pay you back for kWh that aren't generated as per the agreement, and as they often sell SRECs, non-performing panels are a direct assault to their income stream.
I agree, I really like SPWR panels. But that said, the high wattage modules are cutting edge and quite expensive. IF you have a small roof, then they can make a lot of sense. But if you have enough space, the extra cost may not be worth the extra power. And don't forget, SPWR panels aren't domestically produced, so the "made in USA" factor isn't in SPWRs favor either. And financially speaking, for me I was better off with SCTY.
SCTY has several options, including outright buy. If you ask them, you can even lease and STILL get the SRECs. It's all in what you ask for. I found SCTY to be the most flexible and cost effective. Can't hurt to ask both companies and compare. For me, I pre-paid upfront, so for about 1/4 the cost of purchasing outright, I get to use all the power from the panels for the next 20 years, with no additional costs, including inverter replacement and panel repair. Would I have picked different panels and inverters if I were buying it for myself? Yep. Would I have over engineered it and spent more than I should doing that? Yep. But I discovered after thinking long and hard, all I really want is cheaper electricity, and after crunching the numbers from several different vendors, pre-paying from SCTY made the most sense for my situation.
Well, to each his own. If you like SPWR panels, buy 'em. But, if you don't really care about who makes the panels or the inverters, and you trust SCTY to back them up and be around for the next 20 years to service them, then it makes sense to give SCTY a call. To me, pre-paying for 20 years worth of power made the most sense. I could buy outright for 4 times the price, and still get the same amount of power in the end. The only down side I could find was that I didn't get to pick the panels and the inverters. I decided to trust SCTY to engineer it to work for them, and that works for me.