I thought I’d actually contribute to this thread 
Sooooo, LEDs actually have a pretty long lifespan as long as you drive them at reasonable voltages / currents and keep them ‘cool’ (yes, body temperature isn’t ideal, but it’s not 70 degrees C) - should we get a way to power LEDs for a while (e.g. beta-voltaic cells or supercaps) it would probably be ok, but not super bright. Commercial LEDs are driven pretty hard, for efficiency, cost, brightness and it doesn’t hurt that it builds in obsolescence.
Note its not coming back, but there was once tritium implants which would glow for a long time (6 - 12 year half life). There are some safety concerns though…
Fair warning - the more powerful / newer / better chips (including the one in the upcoming Apex line) have documentation / specifications under NDA, and there’s no way around that… it’s up to you as to how much that matters to you. Personally, it annoys me, but it’s down to the chip manufacturer (NXP) not Dangerous Things, and I want the functionality / security, so I will be buying.
Something to consider - I have both and xSIID and xLED in the same position (L0) - I like my blinky! Here’s a picture:
For Android, the most common apps are NXP TagInfo and TagWriter, and NFCTools.
Honestly, like @darthdomo said, the NExT is a great chip to begin with, mainly because it’s two implants in one. You may want to have a look at the implant bundles if you also want a spark… the red or white bundle could be quite suitable. However, make sure you understand any limitations of the Spark, because there will be a new / more powerful Vivokey implant series (the Apex) coming out sometime soon(ish).
Oh, and like others have said - if you want to do much LF (i.e. the xEM side of the NExT), get a PM3 easy - seriously, its so much better / more powerful than the bluecloners, and it’s also suitable for a xM1 if you decide to get one down the line.
One last thing - if you want to figure out what your current ID cards / badges use, do a full scan on them with the NXP TagInfo app - if they don’t scan, they’re LF (probably xEM compatible), if they do it will try to identify the chip used. If you post pictures of the scan / tag, we can often make recommendations (blur the UID though)