Two big questions for you:
1) How long are you expecting to use this <$200 phone?
2) What sort of user are you? (Okay, this is actually a multi-part question...) How important are various variables (heh) like performance, camera quality, battery life, OS updates, durability, etc to you?
I've had a N4 since they came out (~November 2012, if I remember correctly?), and I'm still using that as my daily driver. I was briefly tempted to upgrade to the N5 (and again with the N6), but for now (at least) I continue to be pretty happy with the N4 - particularly since it has been confirmed to receive the 5.0 Lollipop update.
That said, it does have some obvious drawbacks when compared with newer devices. The camera can be kind of slow to do much of anything (launching, auto-focusing, and snapping pictures), and the quality may leave a bit to be desired. The battery life isn't anything to write home about. And while the phone doesn't generally lag when performing day-to-day tasks, some more intensive games may lag or stutter.
Honestly, if you're looking to get ~2+ years out of a sub-$200 device, my strongest recommendation would be for the Moto G, which can be had
new for ~$180.
Moto G (2nd Gen.)