From what I have read, the SD card problem is related to cheap SD cards and the slot being over the processor. The processor heats the cheap cards up and causes premature failure. A class 10 SD card is the best solution on this. As far as any glitches in the software, I would suggest removing one app that you have installed at a time until the glitches stop. That app would be your problem. Viruses, that would be an issue with your downloading choices. Stay in the play store for apps, fewer problems. When in doubt use an antivirus app, several free options.
Anything else sounds phone specific and may be an issue with your specific phone. I have great reception with my Note 2, of course I am on LTE 90% of the time in a rural area, and my battery is even better since the 4.3 update. I typically have at least 30% left after 14 hours with moderate use and being indoors.
I took my Note 2 into be looked at two days ago because it's responsiveness had become some what laggy, especially the home button. I didn't have time to leave it though. I had also started seeing more battery drain. I was told to be sure to remove the battery every so often. I hadn't made the upgrade connection as possibly being the source. My connection can be hit or miss sometimes, but I do live at the base of a mountain here in Northern CO. I think my network at home is the cause of some of the connectivity issues. Comcast makes me angry. My signal was awful in SC this past summer, but my mom lives in the boonies where Verizon typically has the "best" coverage, but that's not the greatest either. What did perplex me is going into Columbia and still having a poor signal. I was told when I got back to CO that I needed to refresh the PRL when I travel. Luckily, I didn't experience the card issue or any other funky issues. I ended up leaving the Sprint store two days ago with a Note 3, just because I switched my plan. I'm glad to have had this phone and to have the new one. I hope you'll be able to resolve your issues.
I got the "Update your PRL and profile". I get poor reception as well. I live within 3 miles of a 4G LTE tower. This phone is garbage, and Sprint won't upgrade me to a different phone without making me pay an exorbitant amount of money because "I'm not eligible for an upgrade" even though I brought back this phone with this and a fast battery drain issue before the 2 week new phone trial period. Horrible customer service, and horrible phone. Lesson learned (the hard way). I can't wait till the contract expires.
I also get really poor reception lately, over the last year or so its steadily gone down hill. Sprint turned on 4G in my area about 2 weeks back and i get OK data speeds now but my phone reception still stinks it goes 1 bar 0 bars then every now and then full bars just for like 2 seconds and then back to 0 and roaming on occasion too. all this in the same house where we used to get 3 to 5 bars consistently. we now also get dropped calls every now and then too.
This happens on my Note2 worse than the GS3 GS4 and my wife's new GS5.but all the phones don't get as good a reception as it used to be.
I switched to Sprint from AT&T less than a month ago and have been SOOOOOOO disappointed ever sense. The service on my Note3 is absolutely TERRIBLE. Regardless of where I am I never receive decent service. The phone is slow, it glitches, and I don't even have the basic features that I previously had. I'm extremely disappointed and it seems the switch was a terrible decision.