The first two are the same, just different branding.
The third one uses wider glue sticks. I would guess that a wider glue stick implies a bigger nozzle. So for smaller spot jobs go for one of the first two, otherwise the last one.
Little tip: When using a glue gun, as the stick gets pulled through, glue the next stick to the end of the one in the gun before it gets to the trigger mechanism. I.e. get new stick, put blob of hot glue on the end of it, and attach it to the one inside the gun. The trigger mechanisms don't tend to work very well going from one stick to the next unless you do this, or use a free hand to push the new stick whilst pulling trigger.
Another tip: Buy a stock of sticks, as they seem to evaporate! Seriously though, when doing a hot glue work, you'll be surprised how quickly it gets used up.
The purpose of a little toe is to ensure you keep your furniture in the right place.