Technology: Objective C
Portability: Nil. If I write an iPhone game for the iPhone, it stays on the iPhone forever. If I wanna later move that game to Android or Blackberry or Windows Mobile, I rewrite it.
Pros: It's Apple-approved
Cons: I friggin' hate Objective C
Price: $99 for the developer program (and I presume this $99 will still be necessary for all the other technologies below.
Technology: Torque
Portability: Maybe. I haven't seen anything saying that Torque will be available for other portables, but it's certainly do-able.
Pros: Available right now
Cons: Requires a 5-second ad for Torque to display before the game starts
Price: $500 for the iPhone engine. $250 for Torque Game Builder.
Technology: FlashGap or Appcelerator Titanium (yes I know they're different in that FlashGap uses the existing browser and Titanium bundles its own browser, but they're conceptually similar)
Portability: Quite good. Titanium hasn't nailed down their mobile plans yet, but I'd be surprised if it didn't include pretty much everything. It's currently desktop-only but I suspect that'll change.
Pros: Would probably be the simplest way to get my games up in a hurry.
Cons: Apple is denying FlashGap applications on general principle, and that's a big deal-breaker. No word about Titanium yet, but if I don't get word that they're working with the content police that they won't be FlashGapped, then I'll have a problem.
Price: Free
Note: There's an Appcelerator Titanium beta launch-party here that promises to have "A Big Surprise". Whether the surprise is something at the party or is something having to do with Titanium isn't clear. Here's hoping I'm pleasantly surprised.
Technology: Haxe for iPhone
Portability: It's apparently using GCC as its compiler backend and SDL as its display-layer, so provided SDL gets ported, it will likely get ported too.
Pros: Would probably be the simplest ways to get my games up in a hurry. . .that's actually compiled and would be approved by the Apple content police.
Cons: Is just a proof-of-concept now. Has a truly frightening build-chain to get from Haxe code to iPhone native.
Price: Free
Technology: Unity3D
Portability: Haven't heard any indication that it's moving to other platforms, but I wouldn't be surprised if it did.
Pros: Seems like the most mature of the lot and there have been some very impressive games done with it.
Cons: Is 3D all the way, but I've seen 2D stuff done with it (presumably just ">very thin 3D objects). You have to open your game with an ad for them unless you pay 'em another $2500
Price: $200 for the IDE and $400 for the iPhone engine
So, did I miss any technologies? I know there are a few "infant" technologies out there, like a Ruby and a Python interpreter, but those looked pretty far from mature and even if they were, they'd likely suffer the same problem as FlashGap. Haxe would fire on all cylinders if it wasn't just a proof-of-concept.
The other question is what to develop first. Shelly's of the opinion that I go with Android first and do iPhone second just so I could be a bigger fish in a smaller pond. Of course, this would affect the list above pretty greatly. It'd also be quite a bit cheaper. Far as I know, there's not an Android development technology yet that costs money :)
Comments are welcome.
I think the Haxe option has got legs, but it could be a while before it is in a usable state in terms of performance for a full game. Torque would be my top choice right now.