I wouldn’t worry too much about storing the fuel in your bag Seb, as long as the bottle is half decent.
I’ve got a Bushbuddy and I love it, but it’s a bit quirky. It’s light and fits in my potset, but I’ve had a bit of trouble getting it going at times. There’s also always the concern about lighting a wood fire in the bush, but in my view the flame is well contained and safe. It makes your pot all sooty too, but I use a cosy so that keeps my stuff clean. I like it because I can properly cook on it. It heats water quickly, but I can control the heat by controlling the amount of sticks I put in so I can simmer away some dahl for as long as I like.
I also have a remote tripod gas stove. It’s also great; boils water quickly and simmers easily, but yeah, you need gas canisters and a windbreak. I prefer the remote tripod to one that screws on top because it’s more stable and the windbreak is safer/easier, but it’s heavier/bulkier.
Having said all this, for ultralight travel, I’m pretty convinced by alcohol stoves now and will be looking to get a good setup soon. That Tier Gear one someone linked too looks like a great setup. I’ve met people traveling with Zen stoves though and they’re so great. So simple. I’d always worry about how much fuel to carry on a big trip though, but really, if you’re stuck and you want to cook, just light a little wood fire and cook on that!