Incurrently use deans on the battery side of things with the watt meter to controller
Any other connections thanuse a frequent connect and disconnect I use power poles or Anderson connections which are holding up pretty well.
Deans are ok for live and negative connections as you can't hook them up the wrong way round that easily.
However I don't think there rated to high on the amp front. Anyone pulling serious amps usually uses the bullet connectors or ec3.
But deans feel a bit more solid and in most ebikes you wont pull much over 30amp at a max. Not the same as helis pulling 100+ amps.
You can buy deans connectors from places like
rc supplies uk
Doubt there the cheapest but super fast delivey and uk based.