Day 1 buyer of nexus 5 here coming from iphone 4 using Straight Talk. Positives first, nexus 5 on ST is fast LTE. It's got the snappy. Screen is really nice, great to upload videos without having use handbrake to decode for iphone.
Here's the negatives compared to my aging iphone 4. Vibrate is weak, I'll catch vibrate 95% on iphone, nexus I miss about third the time. Headphone volume is super weak on nexus. I have to use my Sennheiser cans cranked sometimes to hear a video that would play on my cheap earbuds similar volume at 50% on ipad / iphone. Matter of fact the volume makes it damn near useless to use at gym even w/ my best earbuds. Battery life is not good, its a lil less than my current iphone 4 after 4 years of hard life. Onto last negative which makes me regret this purchase. Its the "Glass Joe" of durability. Nexus on passenger seat car, hit brakes it hits padded leather glovebox, falls less than 1 foot to thick carpeted floorboard. Thought nothing of it and never had a phone break from such a weak contact. Screen done and out $180 to send back LG in Ft. Worth. First broken mobile device I have had in 30 years+ of ownership going back to Walkmans and ghetto blasters. Every phone I have ever owned (old brick ones, flips, razr, blackberries, iphone etc.) would have taken that fall no problem.
Nexus should be back shortly and have Spigen neo hybrid case and caselogy case arriving. Honestly have no faith in the phone even with cases coming and if Glass Joe acts up again its gonna take a few .45s for fun outside.