1. Continual droppage and reconnecting of Wifi at home. No matter what i've done and no matter what wifi network I connect to, my Note 3 continually just "drops" and "reconnects" to wifi, and YES I have taken off the smart switch. This problem has been continual even after 3 Note 3 replacements. Using a Asus N66U with 3 other wireless devices that have no issues on 5ghz and 2.4ghz. Note 3 issues with mine continue no matter what location including:
Various starbucks,
University campus
Bus stops
Restaurants.
Sisters house
Some of this can be due to the hotspot. I notice a lot of public hotspots are just... terrible. Even at the facility I train its like that, on both my Note 3 and my M8. Sometimes the phone cannot connect at all (always have 2 phones with me, so I know the Note 3's WiFi is not the issue).
See the Issue at McD's, Panera Bread, Starbucks, and other places.
2. Horrendous camera quality. My Note 1 would take awesome photos, even in low light situations. My Note 3's camera quality all around is outright terrible. 90% of my decent indoor lighting shots are blurry or smudged, and you can pretty much guess that low light shots are utter crap all around with very high amounts of ISO grain noise and not to mention poor contrast and outline of subjects. Only in very nice, outside sunlight days does my Note 3 give me decent quality shots. Beyond that, it sucks, VERY hard.
Turn Smart stabilization off on the Note 3, many people it seems have issues staying still while the camera is processing (it's almost like HDR, you don't move until its done). It takes decent photos as long as it isn't dark.
And I cannot take seriously someone saying a Galaxy S2 'S', which is basically what the Note [1] was, takes better pictures than the Note 3, cause it didn't.
The Note 3 actually doesn't go up to ISO levels as high as other phones like the Xperia Z3 and HTC One M8. It does use Image Stacking in low light if you have smart stabilization enabled. The Note 4 will still be clearly worse than those phones in low light. It still opts for higher ISO and faster shutter speed than even the Note 3 in some low light scenarios, so YMMV. Its camera is clearly better than the 3's though, so it's worth the upgrade if you want a better camera.
It's still not going to be a great point and shoot replacement, IMO, since it lacks Sony's Superior Auto Mode, HTC's Extreme Low Light Prowess, and/or Apple's superior image processing. It's just an all-around decent camera and a clear upgrade over its predecessor (I still think the S5's camera performs better, in many areas that matter (white balance, color reproduction, post processing, etc.)).
3. Crap battery life. Most likely due to KitKat software issue that STILL HAS NOT been fixed with T-Mobile. This has been a known issue about Kitkat 4.4.3/4.4.2 since earlier this year and im wondering if 4.4.4 has fixed this issue, especially on T-Mobile.
I get 6-7 hours of screen on time. About 5 if I'm doing lots of more aggressive things with the device with the latest KK update. My battery life went up with the update, not down. I do factory reset after every update, though. I recommend.
4. SLOW SD response/reading/writing. I've used two Class 10 microSD cards from Samsung and Sandisk and photo browsing/copying/deleting on local phone or over USB 3.0 and i've been really dissapointed on the overaul performance of Note 3's ability to use a high quality SD card.
That's true for any phone. Sorry, but you aren't going to get USB3 speeds using the SD Controller on the phone - it's really there for going to and from the NAND Flash storage on the phone. For SD Transfers, you're better off taking out the card and putting it into your computer... Most OEMs are not going to use the high end SD controllers that camera manufacturers put in their higher end devices. The cards don't perform that well in the phones. They perform well enough, but generally not at Ultra Speeds (maybe read, not write that's for sure).
Additionally, the Note4 drops USB 3.0 support, so transfers will be slow even if you're going to NAND storage on that device. That goes for HTC and other phones as well. Even transferring to internal storage, the M8 takes forever to transfer large data loads over USB 2.0.
The phone does support WiFi Direct, and unless you have an old computer running an Old Operating system, you may be able to use that to get faster transfer speeds (which will still be bottlenecked by the IO Speed of the SD controller).