Horizontal. Verticle is terrible for most computer screens (landscape)

Yet is amazing for phone screens hehe

Yeah, I can't win. :S

Still, I’d go horizontal heh

You can tilt your phone to horizontal mode, I cannot flip my 31' screen to verticle

I have a 27 inch monitor and always usually have two programs side by side, so for me vertical is better for me, but either way works fine as I can work around it.

The compromise would be getting something where it works in a 2-wide 3-long and a 3-wide 2-long equally but I get that's not ideal either. I think the way Half-Coin has been going so far is fine, but I don't personally mind either method.

It sorta depends on the scenario or what is being shown. Some situations are better horizontal (transformations for example) but progressions in a scene I tend to prefer vertical. I think it's b/c eyes naturally go top to bottom, which keeps the lower panel out of view as long as possible.

Mighty square saves the day! Lol. I vote horizontal layout.

I prefer horizontal because we more naturally take a scene, as that's how our eyes and brains work. I dun care if smart phones are vertical, I still try to take my photos in landscape orientation!

Dominus tecum

Naturally, from a composition standpoint, some content lends itself more to a vertical or horizontal layout, in which case that should take precedence and the following will be moot.

For individual images, it's generally best to try to match the aspect ratio of the majority of target devices. If we include both desktop systems and also all mobile devices that can be rotated with ease, that makes horizontal the clear winner.

For comic strips, and other groups of detailed images where the images are connected but it's not necessary to see all of them at once, it's best to assume there will be scrolling, decide which scrolling direction would be better, and then design layouts with that in mind. For longer sequences, a vertical comic-book-like layout, just like what you've been doing lately, is usually the best answer to this.

None of this is really a rule, though, as the situation changes depending on the content. A little thought and a little experience will generally steer you in the right "direction" though.

tl;dr: You've been doing it right.