@f The one on the right makes the title easier to read, the tiny the on the one on the left is easy to miss. It made Honest Martian sound like a second hand spaceship dealer.
@f I prefer the left one (with your name in green), the other one feels a bit outdated to me.
The orange one feels too Photo-Shop-y. The font choice, layout, and color scheme say planetary invasion zombie apocalypse to me.
I like the retro-feel and composition of the not-orange one better. It feels more inviting.
The font choice and layout is a bit off the mark, especially the green.
The "Humorous Science Fiction Novel by" needs to go. It's too small to read in thumbnail. If you have to say it on the cover, the cover isn't working.
JMO.
The readers don't follow the guidelines.
The guidelines help the author understand what message a reader gets from the cover - usually unconsciously.
Space ship on the cover? SF
Elf, Dragon => Fantasy
Look at best seller list on any niche in Amazon. The color schemes, style of art, layout, color schemes will tell you what kind of book it is.
The trick - like with tropes - is figuring out how to stand out while still sending the message you want to give without becoming cliche.
@f I like the greenery on the orange sky cover, but I like the other cover (where your name is in green) better overall.
I think the reason I like it is because it reminds me of a cover of another book I read that I liked. The "orange sky" cover is not bad, just not as appealing to me.