I'm a Nexus 5 user, and I'd advise you to buy it, the sheer benefits of a Google branded device and a reference android device makes it leaps and bounds ahead. All the complains you've basically ever heard are addressed and fixed by Lollipop. It's worth it bro.
Oh yeah, I always have 35% battery after using my phone moderately the whole day. That includes heavy texting and usual browsing. Anyways Lollipop has a battery saver built in, that provides an extra hour. I've also rooted, flashed a custom recovery, and also flashed franco.kernel; using that I've undervolted my CPU for even better battery life, and that doesn't cause any hiccups too! IMO, it's worth it. It should be a no-brainer at this point