I contacted the Amazon vendor, LaptopMateUK, regarding the discrepancy between their claim of 1900mAh and the measured 1700mAh (and the 1700 under the sticker), and customer support replied that the 200mAh difference in capacity "is within the variable tolerance, it is acceptable".
I also have an issue with the battery, whereby when it is charging on mains, and I hold my Sensation in my hand, I occasionally get the pop-up menu asking if I want to turn off or reboot my phone. I've had this four times now, and my finger is nowhere near the on/off button. I've tested with the stock HTC battery, and I have not had this problem once. I suspect there is some kind of power leakage to the case going on, perhaps the battery is not completely insulated and since the battery presses against the back cover, and then my hand (or the pressure of my hand) completes the internal circuitry to the on/off circuitry.
The charging circuitry seems a bit iffy as well, since it can sometimes stick at 99% for an hour, and only go up to 100% when I turn off the phone.
Then there are the incorrect temperature readings (mine never reads above 25C, when it is clearly much warmer). I am concerned that if it *does* overheat (e.g. if the charging circuitry doesn't shut off) then the phone will not know to alert me to the problem.
So they lie about the capacity and that it's ISO "certificated" and the temperature does not work and there's an on/off issue with my battery... I'm not at all confident their manufacturing standards are what they should be.
All in all, I've decided not to risk my beautiful and expensive Sensation and I've plugged the stock battery back in. Instead, I'm using BetterBatteryStats to identify some battery-draining apps. Perhaps I'll get the new 1730mAh HTC battery when they release their "special edition" Sensation.