PR6's are the bomb! I switched over about 2 months ago from EC5's. They will handle anything you can throw at them. both amps and wire gauge.
You do have to be careful as you can potentially connect two batteries together in series and short them out. At least that is the one complaint I hear elsewhere. You can purchase them in Blue and Red. Use Red on batteries and blue on ESC. Always connect Blue to Red. That way can't go wrong. I bought a ton of Red ones from HobbyKing. Hated doing that but the price was right. I have also bought them from Progressive RC and backbaycomputerguy on Ebay. I saw no difference in quality. I have marked my ESC side connectors with a black sharpie instead of using blue connectors. Either way, Red to Red and your dead
. Well at least smokin!
As with any bullet style connector, heat is your friend. A good 200W+ soldering iron is very helpful and will prevent any cold solder joints. I use a Weller soldering gun rated at 200 and 300W
Cheers
Alan