I agree with you that you can use this thread in any way which is related to the service. But it's also true that this specific topic of yours has been broadly discussed so many times. You can just go back and see what users were asking and what PBMining answered. They are not going to disclose their business plan or any other information on their operation. That's it. It's your choice to decide whether you want to trust them and invest some money or whether you don't trust them and don't invest money.
I have almost 90 GHS with them. Am I sure this is not a scam? No, I am not. But I am willing to take the risk.
Are other services more reliable? Not really. As long as you have your bitcoins in the cloud, no service is reliable. Take CEX as an example. They seem to be more reliable but what prohibits them to just unplug everything tomorrow and keep your bitcoins? Nothing. Do you personally know them? Do you know where to sue them in case they take your bitcoins? No...it's basically the same exact risk you have with PBMining.
I'm sorry but trawling through 960 responses for a very specific point seems rather over zealous. Unlike many others I do not have unlimited time to read through what is mostly of uninformative substance.
Of course it's my choice - no one ever said it wasn't. Doesn't mean I am not allowed to ask for further information.
Cex is irrelevant - I have not mentioned Cex once. I am evaluating PBmining based on its merits and solely on its merits and not in comparison to any other site. And just for the record - to refute your final statement there is more risk if it can't be proved that mining is occurring.
Take this for what it's worth, because I gave my word to not reveal everything I've been told.
But I am completely satisfied that they are indeed mining, and I've a good idea what their model is. I did NOT specifically verify the model I'm proposing here, but they did say I was on the right track. This addresses the electricity angle as well. I now personally know who the people behind PBmining are. I gave my word, so will not reveal that. They feel, and I agree, that due to the small size of their operation and the large probability of being attacked by hackers and other ne'er-do-wells that they have a large security risk by being public. They are indeed mining. It is my thought, again this part is unverified, that they are purchasing somewhere in the neighborhood of twice the hashpower that they sell. This gives them a good margin and a good profit above the costs of operation, thus the ability to sustain. The model being sell enough to keep ahead of the difficulty curve and purchase new and better hardware as necessary and possible. They are running a decent sized farm. If you do the math, even if they are only purchasing 125% of what they resell, they are able to keep ahead of the electricity/difficulty curve and continually expand. This also allows them to turn off or retarget obsolete hardware as it becomes unprofitable while still maintaining the contracts as stated.
Of course, you have little better idea of who I am than you do of them, though my real identity is known to the forum. Nevertheless, I am certain they are the real deal, and I will continue to both buy from them and promote their service.
Come to me my piggies!!!
Edit: Due to the Chuck Norris comments earlier, thought I'd clarify. That is me in the avatar, though I cut off my hair and regrew it since then. It's not blonde without a bottle, so I look a bit different right now

I don't see the resemblence, personally, but I sure won't be offended by the comparison! Chuck might, though.
As long as it's not Mark K from Gox's new venture..
Good to know that the people behind PBM are known to at least some forum members.