AT&T phones can be easily unlocked. I just went to the AT&T store and told them I was going to France for the summer and they unlocked the phone for me to use abroad. T-Mobile is the same, though I've never actually had a phone unlocked. I asked them about it once, they said that if the store can't do it for free, you can get them unlocked for about $10.
The Samsung Galaxy S II that I had before my LG G2 was like 215 ppi and 480x800 resolution. I never really noticed the low ppi. The only device where I notice it is my 10" 1280x720 tablet, and even then, its not so bad. I had a Note II as a loaner phone for 3 weeks while my S II was being replaced by T-Mobile, and I had no issue with the resolution. Yes, my new 1080x1920 LG G2 looks a lot nicer, but the 720x1280 on the Note II is plenty good. I also had a Nexus 4 as a loaner when my S II broke a second time, and I didn't like it as much as the Note. I loved the battery life of the Note II, and the size. I think the Nexus 4 is too small.
Note II camera is on par with the S II, so its a very good camera. 4G was faster than the S II, and the screen size is great for videos.
Desktop: i7 6700K - Asus Z170A - Gigabyte GTX 970 - 2 x 8 GB DDR4 3200 Mhz - Samsung Evo 850 500 GB - EVGA SuperNova G2 750 - Noctua NH-D14 - Fractal Core 3300
MacBook Pro Retina 13: i5 5287U @ 3.3 Ghz - Intel Iris 6100 - 8 GB DDR3 1867 Mhz - 512 GB SSD
Peripherals: Dell UP2516D - Bose QC25 - Poker 3 w/ Cherry MX Blue - Corsair M65
Legacy Overclocks: Q9450 @ 4.0 - Q6700 @ 4.0
OCC - Home of the Potato Overclock