Autolite 26s are not the stock plug and in fact do not fit in the engine under discussion. See tune-up parts and technique suggestions, including spark plugs applicable to your engine, in this thread.
Either the Mopar or GM HEI system will give sturdy reliability as long as it is set up and installed correctly and good-quality components are used. You really aren't going up or down in terms of reliability compared to points, you're kind of going sideways. There's a greater likelihood of mechanical failure with the points system — the points themselves can fail at the rubbing block or at the pivot, a drop of oil in the wrong place can cause the contacts to burn — but it's also easy to rig up a mechanical fix to get you home (chunk of vacuum hose wedged between points and distributor body to substitute for broken points spring, piece of paper run through the points to get them clean enough to work). With the electronic system, you're swapping this for a lower likelihood of failure but the only way to fix the failure is to replace the faulty component. In practical terms, this means carry a spare module of whichever type you decide to use, and a spare ballast resistor if you use the Mopar system. (Two more advantages of the HEI system: the module's a great deal smaller and easier to carry as a spare, and you need no ballast resistor at all).
The HEI article has been revised so it no longer recommends the MSD Blaster coil, which is now made in China
— I'd say that kind of component-build issue is going to be the primary factor in the reliability of your ignition, these days, sad to say.
