The multipoles are great, but bulky. I used them on my SLA setup on CrazyBike2, salvaged from powerchair stuff and UPSs. The smallest of the multipoles uses the same contacts as the 75A powerpoles.
There are also at least two versions of those contacts--one has less pull-apart resistance than the other. I don't know which ones mine are, but they take a fair bit of force to disconnect, and they'll never just accidentally come apart (unless maybe your battery falls off the bike, then they might let go
The different color housings are also keyed, so AFAICR only the black and gray can be connected together, all the other colors are different keys, so they can't accidentally be hooked up. Usually they'd be used for different voltages, but you could also just use them that way to ensure you never hook battery to phase, etc. They are all also polarity protected, in that they can't be hooked up backwards.
For the powerpoles, the 15A, 30A, and 45A are all identical sizes except for the size of the hole in the contact that you insert the wire into for crimping.