I haven't used the HF100, but it looks pretty decent, I recently purchased a Panasonic SD-9, which is similar, although hasn't got the audio inputs you need.
Just thought I'd share my thoughts on someone who owns an SD card based AVCHD camera, I've been using mine for the last 3 months whilst backpacking in the Americas, shooting in many different situations and environments, and I'd definitely recommend it for this type of use.
SD cards are much easier to get hold of, store and backup than tapes, the size is fantastic, ideal for grabbing a couple of quick shots and tucking it away again.
I wouldn't want to shoot a feature film on it, but for everyday use it is the best camera I've owned, I've had 4 tape cameras before this one, and I wouldn't go back to tape now.
The editing of the footage is not that big a deal, I've been transcoding to DV and editing on my low powered netbook whilst on the go, and I'm looking forward to getting back to a desktop PC for some HD editing too, it has been surprisingly straightforward so far, and with most new editing apps supporting AVCHD it should get easier.
The Panasonic gives me a choice of resolution to shoot in, I'm sure the Canon would too, but it's all encoded in AVCHD anyway, so I assume it will still take a fair bit of processing power to edit it natively whatever resolution I shoot in, as such I just shoot in the top resolution all the time.
I don't think there's a better alternative for the price, especially if you are going to be using it as an everyday camera and not just for documentary/news type stuff.
Panasonic SD9, Panasonic NVGS-75, Canon MV600i