I have the original Titan now and it's a great device but I definitely think I will selling it on craigslist and picking up one of the newer devices coming out. I definitely want a LTE phone... i'm disappointed that this "4G" Titan's speed is throttled so a speed increase would be great.
I think I'm leaning more towards the Titan II over the Lumia 900 though. In the looks department, the 900 wins as the much sexier device. But after using the Titan for over four months I don't think I could ever go back to a smaller screen. I could probably go bigger though. The 900's ClearBlack display is definitely enticing but size just may be more important. My Titan's screen is good enough (coming from the Focus) and I actually prefer it over the Focus S'.
The TII's processor is just slightly faster (even though it won't be noticeable to most).
Everyone says that Nokia's camera will be a million times better than the Titan II's just because of the Carl Zeiss name but I wouldn't be surprised if the TII's is just as good or better. HTC has stepped up their cameras and all the indoor shots I've seen 900 so far look really bad.
The 900's battery will no doubt be better. Unless it's a very significant difference I don't this alone will be enough to sway me towards it.
Another reason people are interested in the 900 is Nokia's exclusive apps, but this does not matter at all to me. Those Nokia apps are out there for anyone with an unlocked device to install. I have them on my Titan and Focus.
And this brings us to the last (and possibly most important) thing: homebrew. Right now HTC has a lot more homebrew support than Nokia phones. Neither the second generation HTC's or the Nokia devices are interop unlocked yet though. If I knew I could install a custom ROM on one but not the either, I just may need to go with that one. The 900 is getting a lot of hype though so hopefully that will bring lot attention to it from hackers.
I think the only reason the 900 is getting the attention it has is because:
1 - Sexiness of the device. This is undeniable.
2 - Huge marketing push from Nokia, AT&T, and Microsoft. If you see a device everywhere, you'll start falling into the hype.
3 - Exclusive apps. Important to some, but not to me. Still available to those with an unlocked device.
The only reason the Titan II doesn't have any hype because neither HTC, AT&T, or Microsoft is pushing it. Based on specs alone (when compared to other Windows Phones) it is at the very top of the heap.
I won't make a decision until both devices are launched and full comparisons between the two are out. I'm extremely curious about camera samples and battery life. The camera performance will probably be the dealbreaker for me.
Also the Nokia 900 is cheaper, but I'm willing to spend $100 for a better device.
Oh and to the person a couple posts above me, the Focus S' screen is only 4.3".