It is, in my opinion, a very poor attitude to conflate lunamine's (still unclear) situation with PB Mining's way of doing business.
These are completely separate entities, with no relationship whatsoever.

Lunamine was not paying "non variable" amounts. The increments timings and amounts were consistent with blocks being found with some variance.
PBMining chose to pay a flat rate amount, thus completely eliminating variance.

There is no proof either of them has ever been a Ponzi scheme. PB Mining users have been consistently paid every week without fail, this fact alone makes the accusation of "Ponzi scheme" premature, if not pure libel.

As for lunamine, even now all we have is the word of the owner warning of an attack and some mysterious private problems, but it is nethertheless premature to call it a "scam" or "Ponzi scheme".

And by the way, PB Mining is quiet about his identity, but it is hardly a secret and you can find him easily if you want to have a talk with him. Last: you can find here and there where PBMining is mining. Hint: It's not a self-contained pool, it is mining on various pools (including Eligius). Most miners do the same and diversify/switch pools at their leisure, there is nothing wrong with that.

Last but not least : if you are buying a share in an hosted mining operation, you don't get to see the hardware. Most data center operations are at least partly secret, being related to bitcoin or any other field of business. Most of the time, you'll never get to see the actual networked hardware you're using. If you insist on having a photograph and get one shown to you, you're probably also likely to claim it's a fake etc anyway.