It seems like an easy decision to make -- the Nexus 4 is available for as low as $299 outright. Why wouldn't you get one? But the fact isn't lost on those of us who have a ridiculous number of smartphones that this is still a good chunk of money, and it's quite possible the phone you're holding right this second is still really good and should last a while longer.
So we're going ask the question about a number of current phones and help break it down. Should you upgrade to the Nexus 4?
Let's start with last year's Google phone -- the Samsung Galaxy Nexus.
I alluded to this in our review of the Nexus 4. From the front, we might not blame you if you mistake one phone for the other. Both the Galaxy Nexus and the Nexus 4 are big black slabs, with lots of glass on the business end. It's everywhere else that the Nexus 4 trumps. Like I also said in our review, I've never subscribed to the "Samsung uses plastic, plastic sucks, therefore this phone sucks" train of thought. But it's amazing how much the glass-and-soft touch of the Nexus 4 makes the Galaxy Nexus just seem ... well, old, both in design and feel.
Then there's the display. It's maybe not a night-and-day difference (especially if you're using a custom ROM on the Galaxy Nexus that corrects the color temperature), but it's definitely noticeable. I give the Nexus 4 the easy edge here. My only knock would be that the polarization causes images to appear to shimmer ever so slightly if you tilt the screen, but it's not a huge deal, and you get used to it. The IPS display in the Nexus 4 is, simply, better. The rubber edges give some good grip, too. And you're gonna need it. Whereas the Galaxy Nexus has that textured back for some grip, the Nexus 4 is smooth and slippery.
Edge: Nexus 4
No contest, right? On paper, the Nexus 4 wins hands-down. The quad-core Qualcomm Snapdragon S4 Pro simply is a different animal than the TI OMAP 4460 that the Galaxy Nexus has. Same for the GPUs.
Again, you might not notice that much of a difference in casual use. But in specific, graphics-intensive tasks, you'll feel it. It also means better battery life when you're not beating the phone to hell and back.
Edge: Nexus 4
There's no denying that the Galaxy Nexus is older. It's a year older. That's just a fact, and that means the Nexus 4 should outlive it, in terms of hardware and software. We love our elders, but being younger means more potential.
Edge: Nexus 4
The Nexus 4 is running Android 4.2 Jelly Bean out of the box. The Galaxy Nexus should see an update shortly. That said, there are versions of the Galaxy Nexus that won't see official updates as quickly. (Looking at you, Sprint and Verizon.) We don't yet know how many regional versions there will be of the Nexus 4, but we do know that there aren't any CDMA versions here in the states as of now.
Is Android 4.2 that big an improvement from Android 4.1? Not necessarily. Gmail improvements should be in an app update, and we're still not sure exactly what parts of the Android 4.2 camera will trickle down to the older hardware. You'd definitely miss Photo Sphere if it doesn't hit the GNex. But it's also not the be all-end all of Jelly Bean.
Edge: We'll give this one to the Nexus 4, but only slightly. Even if the Galaxy Nexus doesn't get everything that's in Android 4.2 (and, again, that's not certain disappointment yet), the Galaxy Nexus is running one of the latest versions of the most advanced mobile OS in the world. Don't forget that. (And custom ROMs have a habit of curing what ails ya.)
The edge: Nexus 4 wins, hands-down. End of discussion.
Trading in the Galaxy Nexus
This is the cost of doing business. You're going to have a hard time getting back all of your Galaxy Nexus at this point. But there's a good chance that you could sell it and get a good part of the way (if not all the way) toward a new $299 or $350 Nexus 4. The fact remains that the Galaxy Nexus is still a very good phone, and you should be able to get something for it.
The bottom line
Admittedly, I'm a little torn here, re-reading everything above. The Galaxy Nexus is not a bad phone. And it'll get most (if not all) of the software improvements that the Nexus 4 has.
But also think about what kind of smartphone user you are. We've talked about the kind of person who needs to have a Nexus phone, be it to have the latest and greatest, and to be able to tinker. The Nexus 4 fits that bill, and does so in a way that doesn't break the bank.
If I were you, I'd look to upgrade from the Galaxy Nexus to the Nexus 4.