Sup Chris?
I have a G2. It's still a great phone. It's mostly like an N5 but the screen is a tad larger, the battery is 3000mAh, the camera is better, it has double-tap to wake, rear buttons, idk what else is different.
You'll have to get used to LG's skin/apps unless you root it and flash an AOSP-based ROM (which kinda undos the camera improvement).
I don't find it to be slow or anything, the only reason I'm looking at the next nexus is that I still love flashing ROMs and I much prefer stock Android over the LG (or any other OEM) skin. Plus, the new ones have fingerprint readers, faster processors, more ram, and more resolution so FIDIL.
---------- Post added at 03:58 PM ---------- Previous post was at 03:39 PM ----------
might be of use to you:
http://www.androidcentral.com/nexus-5-vs-lg-g2
Oh and the latest that the G2 has officially is 5.0.2, I think the N5 will be getting Marshmallow. No clue if LG will give the G2 anything newer.