Hello and Welcome to justanswer..
I know the connectors you show - and they are widely used - and are ok ..so long as they are used correctly with the correct size / tool - for the wires being joined. Over time though they can work loose - and especially so if the exact correct one for wire size hasn't been used - or, again, using the wrong one sometimes doesn't even connect , not cutting into the wire to make contact.
Another issue with these is they corrode if exposed to the elements or any moisture.
A better type that is widely used -is HERE
using the same site. These crimp the wires - rather than cut into / through the insulation and provide a better join though you have to bear the ends of the wires to be joined first of course. Too , with these you can buy . use insulated ones.
Its also important to use the correct size - and the correct tool for these.
Soldering remains the best way though - with a heat shrink cover or good insulation tape or self amalgamating tape for a sealed join. It does as you say though, take a lot longer overall. . but thats another option, better connector than the others as above...
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.Kind Rgds to you - MIKE.