I was just wondering and contemplating getting a grab & go setup that could be easily taken and setup at real dark sites. I was looking at the simplistic Meade ETX125 and like the idea of being able to use 6AA batteries.
I don't normally think of Go To telescopes -- or for that matter, any telescope with motors -- as being simple. But within that arena, the Meade ETX series is certainly pretty clean and classic. Its major competitor is the Celestron Nexstar series; I have no opinion about which is better. I also don't know how well either one actually runs on AA cells.
Note that both Mak-Cas and SCT designs have exposed front corrector plates that are extremely prone to dew. Most people who use either one extensively end up investing in dew heaters, which require more electricity than the motor drives themselves.
If viewing from modest light polluted areas that viewing galaxies and nebulae are dim and lack luster. I am wondering if using the same setup and viewing from a really dark site that the 125mm will be MUCH better visually. Would galaxies and nebulae pop out.
Any and all telescopes yield dramatically better views of nebulae and galaxies under dark skies than in urban or suburban conditions. The difference is impossible to overstate. Whether it's fair to say that galaxies and nebulae "pop out" is a matter of opinion. Most or all experienced deep-sky observers would surely say yes. But many novices find galaxies and nebulae disappointing -- and maybe even invisible -- even when viewed through huge telescopes under pristine skies.
The SCT design scales up more gracefully than the Mak-Cas design. So while Mak-Cas's are utterly dominant in apertures of 90 mm and less, most people prefer SCTs when the aperture gets significantly bigger than 5 inches (127 mm).
That all assumes that you're staying within the electronic Go To arena, of course. If you were to abandon that constraint, Dobs become by far the most popular choice in large apertures.