I'm debating getting N9 for myself and my wife. I've had N900 for a while but have not used it much (mostly relied on my iPhone 3GS).

So has my wife. She mostly browses web, does twitter, and uses a few other iPhone apps (eg, Runkeeper).

For my purpose N9 would be great (plus we can probably use it on our $4.99 T-zones data plan). I'm not so convinced about a non-techie user such as my wife. Lack of apps is my biggest (potential) concern.

Any opinions about N9's general usability in this context?

N9 is for non-techies. Not that much apps, but basic stuff (phone, sms, im, email) works great.

Take a look at the Nokia Store . You can select the N9 as your device and browse the apps available. There's getting on towards 700, which isn't bad for a device that's only been on the market, 2 months? I'm biased, it's a beautiful phone and I love the UI and simplicity. P.s I'm no techie, just a N9 fan

Just make sure about the data plan availability since T-Mobile has changed their plans recently and, at least for pre-paid, they have decided to stop offering their Web2Go day pass (for being very affordable), so it wouldn't surprise me if they had gone through some changes for their post-paid data add-ons as well, so just check first.

As for the N9 hardware, the phone ships with a firmware version that is not the most current, and if your device happens to have any sort of branding, this means you would need to follow a flashing procedure, though not that hard, it is definitively not meant for non-techie people either.

Oh, and then we have the micro-sim thing, again, nothing impossible, but it does require you to go through some loops for having either a T-mobile regular sim card trimmed, or requesting one from T-mobile. Not the smoothest instantaneous procedure if you ask me.

So please keep in mind all this when making your decision.

My opinion is that the N9 is much better in this aspect than the N900 (although the cssu has done so much I can finally recommend it to non techies too)

I've used all my smartphones with no issues on tzones and the N9 is no exception. Your local Tmobile corporate store will give you a microsim for free and activate it with no hassle.

As Petteri says, non techies are the N9 target audience. Your wife will have no problems using the phone.

And really only started rolling out in proper no's for about 1mth.
There's was serious ramp-up/constraint issues earlier on, much better now.

I'm a non technie & happy with my N9. I've even successfully downloaded & run some apps which are not from Ovi Store like Open Video Player, Opera Mobile, Firefox nightly, VLC Player. N9 has tutorial guides here, everythingn9.com & my nokia blog, it's not hard, just treat it like you would your PC.
Plus I dont have a N900, Maemo/Meego is new to me. Being a long time Nokia user helps though, as the contacts, calendar, messaging stuff are as per the usual Nokia format.

Dont worry about females 'not getting it', as long as your wife is computer literate, can do some simple troubleshooting, willing to explore, no problem.

Your wife will like the looks. Howeverf the font is ridiculously small and if she is into bigger and clearer fonts, iphone is better. the resolution is better than 3gs but worse than n900 or iphone 4

The res. is not worse than the N900, the pixel-density is slightly less (251 Vs 267 PPI).
There's a heck of a lot more to screens than pixel-density, several other metrics are v.important.