Damn cheap DID chain only lasted 15 miles on my dragbike............
An 'engineering note' here: Tensile Strength is a good comparison for chain LOADS, but not necessarily for chain WEAR. The chains with the highest tensile load ratings are made for slow-moving, non-reciprocating motions, like for dragging heavy things.
That seems not to be the case with motorcycle drive chains Mark, or HD primary chains for that matter, the highest tensile strength is for the strongest motorcycle chains for the highest HP out put. All the best motorcycle chains are around 10,000lbs tensile strength or more, and are rated at over 200HP..... the big 630 Drag chains from EK have a 30,000lb tensile rating.... Our Bikes produce no where near these HP figures so these high tensile O or X ring chains should last far longer than any old conventional style chain... 
When they are referring to tensile strength of a chain, would that be the same as tensile strength rating for a given piece of metal...? Maybe it has a different meaning or value with drive chains..? I'll throw another factor into the chain wear debate, misalignment is also a chain killer, the marks on the swingarm aren't very accurate and can lead to premature chain wear due to the wheel being slightly out of alignment......
You're catching on to the clues: when the chains are very rigid (i.e. highest tensile strength), they are also very unforgiving of misalignments. When run misalinged, they get hot very quickly of their own volition. We see this often when building industrial conveyor systems that carry heavy parts on pallets: if the conveyors flex too much, the rigid chains often get hot and wear quickly. The choices then are: stiffer conveyors (lots of $$ involved, often not done) or use lesser-(tensile)-strength chains (more often done). What has been happening in this arena of industry these last 'leaner' years (poor economy) since 2008 is: sloppier chains (i.e., those that have thinner sideplates, so they flex more) in an O-ring style have been used to solve a couple of these installations that I have seen. The weaker chains, less than half the tensile strength of the original chains, have lasted several years now, where the first 2 sets of 'stiff' ones lasted less than 3 months each. And, they run cool to the touch..
This was the heart of the "Diamond XL solution" for the CB750 in 1970 when these bikes, with their less-than-rigid frames and swingarms, were flexing the RK chains sideways with their rigid, small-clearanced sideplates into oblivion in 4000 miles or less. The Diamond chain, made for the Sportster 1000 specifically, had super-hard rollers added, but with increased ID clearance over the pins, and the sideplates became hard as nails and quad-staked to those pins, but the clearance to the links themselves was doubled over the ANSI spec. This created a chain that could be twisted sideways more than 10x its width over a 100-link length: RK at the time considered 3x to be totally worn out in comparison! The difference made history, and the Diamond chain with its thinner sideplates was rated at 80 HP in 1970 where the RK heavy-duty plate type was rated 70 HP. Today that same Diamond is rated over 100 HP, and I (among others) have used it in O-ring form on industrial equipment to solve problems similar to the 750's chassis woes of that bygone era.
Tensile strength should be considered with the plate clearance questions as well, IMHO, lest the old demon resurface here!
Poll