Is it still worth buying the Nexus 4?

I am interested in the Nexus 4, but with rumours of a Nexus 5 coming out in May, as well as the recent releases of devices such as the S4, HTC One, Xperia Z and so on, is it still a good deal?

I currently have an iPhone 4S and will be looking to upgrade shortly.

For me, I think it's a question of what you really want. If you want the latest cool tech with maximum wow factor to impress your family, friends, acquaintances, and informed nosy people on the bus, then wait and get something else. The N4 was the top of the heap for a few months, but has been, and will be, eclipsed over the next few months by the Samsung, N5 and other offerings. On the other hand, if you just want a beautiful, functional phone, the N4 is it.