Pros and cons of either protected or not. The pcb is for over and under discharging so for example it may trip at 2.5v and 4.25v. Most single cell(multi to) lights these days have some kind of safety cut off or warning. Be it flashing light, loss of higher modes etc. To get a cell down to 3v which is above manufacturers minimum V take some doing tbh......
Many prefer protected cells in multi cell lights that may run in series. Depending on the user their choice could be either type of cell. I prefer unprotected in single and multi cell lights, higher drain cells basically.
Regardless of protected or not, practice should be the same which is not deep discharging the cells regularly . This can shorter the life of the cell/s over time. Learn the light, check the V at set times to get an idea of the voltage used between charges . For example you may use medium for 5hrs over a week. The voltage may be 3.6v and so you know you can charge the cell up weekly. Or you may simply prefer to top it up after each use , or every other day......
Protected are a few mm longer , some lights they can be a tight fit! Same with some carriers ,but of a squeeze to get the 70mm cells in. The unprotected may be 66mm long and fit a lot easier and may sway your choice. The savings per cell of unprotected might too.......Protected also have a slight drain due to the pcb and it's also something else to fail for some people ,who need to limit failures due to their actual use.
So no IMO protected are not better, depending on the application they have their advantages but that's it for me. If the user is dependable on the pcb to tell them the cell is low by tripping, then the chemistry is wrong for them .
Just as important as good cells from reputable shop/seller is the charger! One that works to spec and terminates to spec without trickle charging .
There really is no art or requirement for a degree , just a read up , an understanding , common sense and ideally a tool to measure the voltage away from the charger to aid fault finding and simply to have another form of measuring the V. Lot of good chargers have a V readout, might be enough for some.
Limitations wise, too much amp can trip the pcb (2 ways of looking at it as tripping due to too much current is also a good thing). So some lights protected cells are not a good option. Also if a strip down the side ,its susceptible to shorting if damaged .
Regarding choice of which to go for would depend on what light ,what type of use . From this I would make a decision on which type of cell.
Thats a a brief take on it from me, not saying I am right, just the way I look at it.
Typed on an iPhone so god knows what *beep* it's changed !!