I have a Space Phone. It's Space Hacked. I can do Space Sh@t with it. It's battery life kinda Space Sucks though.
Which carrier are you on?
If you're going for Android, and shooting for a Space Phone, I would settle for nothing less than the following:
=Tegra 3 or Snapdragon S4 Pro (both quad core...which actually improves battery life)*.
=AMOLED. Of some variety. Even PenTile. AMOLED just looks
so much better than LCD. (AMOLED is an LED-backlit screen type, for those who don't speak Space Geek).
=It doesn't matter what version of Android your phone comes with, because you're going to hack it and install 4.2.2 (which is higher than what it comes with, unless you're rocking a Nexus 4).
=MicroSD card slot if you can get one. These are a fast-disappering luxury on high-end phones for some dumbass reason. If you can't get one of those, you'll want to pick up a high-capacity flash drive and
one of these.
As far as brands:
=I love HTC's build quality and form-factors. But they have a vendetta against the hacking commnunity so their phones are among the toughest to hack out there. If you're looking for something you can just one-click root, you don't want HTC. My phone's almost a year old and we just BARELY got S-Off for it (Space Geek for "you can do what you want with it"). And the hack for it is ugly. If you like command-prompts, ADB, Fastboot, and terminal emulators, though HTC is your go-to brand. fastboot flash boot boot.img ARGH.
=Samsung has great marketing and slick, powerful phones. But their build quality is very offputting--very plasticky phones without a lot of heft. My sister's GSIII feels like a toy compared to my aluminum-bodied HTC One S.
Also, depending on the phone you get (though not including the US Galaxy S3) you often end up with Samsung Exynos processors. These are used almost exclusively by Samsung and don't have a lot of "aftermarket" support. Which means Sammy phones often get late support IF they get it at all. Alternatively, stuff like Snapdragon or Tegra are used by just about everyone on earth except Apple, so support for them is excellent. It's like a Chevy small block versus a VH45.
But the Galaxy S3 in the US does have an S4 Pro (that's definitely not a confusing statement), so it's a safe bet for most things. Also has a gorgeous screen. You just have to get over that cheap-feeling, unapologetically Apple-wannabe, extremely ugly white case with its goofy one-real-button-and-two-touch-buttons setup. Who decided white was the new chic electronics color anyway? Looks like crap. Black or silver or GTFO.
I love my HTC One S. Snapdragon S4 (the dual-core version as opposed to the quad-core Pro). 1GB RAM. AMOLED (PenTile, but it still blows away my Nexus 7's display). Hacked and running Android 4.2.2. It's thin (I find myself thinking I left it somewhere when it's in my pocket because I just don't notice it). BUT the battery life sucks. And out of the box it has cellular radio issues which means signal sucks. But you don't buy an Android phone to keep it stock. That's like buying a boosted car and not messing with it.
*Technically Tegra 3 is pentacore, but only four can be active at a time. The fifth core is a low-voltage unit designed to conserve battery during sleep and lighter activities.