Screw on banana/spade connectors

I would not hesitate a moment to use a ferrule/screw tight termination.  I feel this is a superior method to a soldered spade given the same metal make up of the spade.  I hope mr. millercarbon has removed the brass connectors on his speakers, amps.  And God forbid the brass rca plugs, speaker tabs, etc.  There's no end to the ways an audiophile can lose sleep!  
Seriously, for DIY this is a cleaner more conductive method than a blob of poorly applied solder on a large gauge conductor. 

Millercarbon hath spoken.

The locking bananas are ultrasonically welded on the 4S11 at BJC. Works for me.

One can learn how to solder cables to connectors properly.
It does take investment in the tools to do so.  These likely will cost less than what's being soldered together, but that's just a guess....about the parts, that is...
A bit of practice, et voila!  A permanent joint

If it's temporary, 'screw around'.
If it's soldered, it's Done. Back to fun....

...but this is fine for 'normal' cables and connectors; esoteric items are best sent back to their home planet, where the 'natives' know-how...
...and charge handsomely for it....

Ask yourself how much solder your electrician used in the 250 A panel at your service entrance.