According to the 1.4x rule an 80mm ED doublet can equal a 112mm reflector. I don't know who makes these rules up, but it sounds about right to me. I've long believed my Evostar 80ED DS Pro was better than my 130mm Newtonian for planetary detail.
I don't know that I have heard of such a specific rule; it sounds off to me. There have been some claims about subtracting the central obstruction diameter from the scope aperture (linear relationship), but I don't find that particularly accurate either. I suspect that some such guide is providing your 1.4x factor, although that would again depend on the specific obstruction.
I have an Orion 80ED and a 127Mak (ES f/15 variant, a version of the Meade ETX 125 design but with a better backplate for collimating.) The 127's run about 40% obstruction, which is due to the secondary baffle diameter, not the mirror spot diameter. The ES/Meade based design operates at/near full stated aperture in the 127mm range, while the Synta f/12's might still be undersized with respect to their primary mirror IIRC (hopefully somebody will correct that if I am mistaken--there have been some differences at 150 and 127mm.)
While the 80ED puts up good planetary images, it is no match for the Mak with respect to planetary detail. Some Mak afficionados claim they are equivalent to the same aperture refractor, but I am not among them. My 127 puts up somewhat less detail and is somewhat less sharp than my 110ED f/7, but it is close on good nights. The 110 is an FPL-51 doublet and has some color, so it doesn't reach quite the same optimum planetary magnification/inch that the 80ED achieves. The calculated effective light transmission of the 110ED and the 127 Mak are nearly identical, but the contrast is better in the refractor, allowing it to go a notch deeper.
The Mak required collimation when I received it. This consisted of an initial tweak on a mediocre night (first light), then fine tuning on a better night to dial it in. The Mak design is thermally sensitive and that can be an issue, particularly in winter, although there are some ways of addressing it. The focus adjustment on the ES Mak is somewhat cludgy, but workable once you have a feel for it.
Seeing here in the backyard is usually lousy, so the 80ED serves the role of seeing scout for planets. If it is decent in the 80ED I will bring out the 127 Mak or 110ED. The portability of the Mak leads me to use it more than the 110, if the weather is cooperative (not expecting significant thermal issues.) If thermals are expected to be an issue then I skip the Mak for the frac. And if the seeing is steadier I use an 8, 10, or 20" scope.