The last one is my old toaster style MPX3. Is it bad, yes, but it worked fine. And you can see how the quality has improved since then.
There are plenty of reasons not to buy from SP, but yours are not one of them. I fail to see how having an overbuilt chassis is a bad thing. Your chassis comments also make no sense, Justin can take that long because he is a one man operation and a perfectionist, while Mikhail and Ray cannot? Kevin Gilmore doesn't even make amps, and your constant pitting of SP against EC is getting old. Please stop getting into pissing contests whenever somebody brings up another tube amp manufacturer.
To answer the OP's question further, the best way to go with SP is definitely to buy used. Because the product itself is great, but the hassle of getting one new is unbearable. Try to find one that already has all the options you want, and make sure that any upgrades are ones you absolutely want and know will make an improvement, and have been done before to your particular amp. Good luck.