I personally have great luck with the XT60's. It is important to get quality ones, ones that won't melt down and deform during the soldering process. For the ones I bought, they had solder cups that held dual 16 gauge wire, no sweat. For reference that's Monoprice 4 conductor, with two conductors per side soldered together. Quite a bit of copper IMO.

Here's some finished:



The only thing I didn't love about these cables I made is the semi-opaque white heatshrink.



I debated back and forth with the EC3 vs. the XT60 and Deans, etc. Also, the Traxxas connectors, they can be an option as well. I like the simplicity and compactness of the XT60, that's what sold it for me.

I use a "helping hand" device to hold the wire, and solder it to the cup. Near impossible to to with two hands otherwise.