Hmm....I like these sorts of comparison questions - they stretch my brain!!
I had the Cameleon - it was my forever pushchair (until I had another within 2 years and realised my plan to buy a board with seat on simply was never going to work and it had to be sold.
I thought the Cameleon was fantastic and even now, several tens of pushchairs later, I think I will end up buying another. There's no real logic to this except that it was pretty, customisable and it did kind of work. There was so much good eg lovely carrycot, big seat unit, lovely to push, big bag/basket, small flat fold, flip handle (I miss this sooo much!!), handbrake, reverse wheel mode, the seat lifts off to be an impromptu highchair, 2 wheel mode etc. Some bits werent perfect like the fold isn't the easiest (reading the instructions always helps!), I didnt like how the childs head rested on the hood fabric, and it was only when I then moved onto the iCandy Peach that I realised how solid the Peach felt in comparison to the Cameleon. I dont think I dare say the Cameleon feels rickety - because compared to the Bee its solid - but moving to the iCandy's I discovered solidity and sturdyness that the Cameleon doesn't have. Thats not to say there's anything wrong with the Cam - it just is a different beastie. I think the way to substantiate that is by having the two pushchairs in the shop next to you.
So to move onto the Apple. I will be honest and say I haven't had a true Apple, but I have had a Pear which is a similar chassis and near enough to have an opinion!! I have played with Apples as well. The Pear was a nice pushchair to push - it has the sturdyness and solidity that I was talking about. But its also quite a big pushchair. The chassis folds fairly large too. The basket is a good size. The seat is large and has a good adjustable footrest. So should last you until the end of your pram pushing days, whereas I always wondered if the Cameleon would without removing the hood. Some Apples are customisable with flavour packs (the newer ones). The Pear (and I have been hearing even tonight that the Apples too) had large straps. This is something I want to have a closer look at this weekend because straps need to be close fitting otherwise there is no point to having them. So this is something to look at. A lot of people have issues with the fold. I never have, but there is a knack to it and you really need to try it to know it.
I think feature wise, both pushchairs are high spec. Both are good quality brands. Both should do a good job. I think the choice goes down to personal preference. Don't choose the Apple just because it could become a Pear, because the upgrade kit is expensive. If a second child is an option, then I would be steering you towards the Peach.
I would have a really really good play with both, make sure you - not anyone else - puts them up and down, and also that you lift them into your boot (I know you are pregnant but its a good test). Make sure you can recline the pushchairs easily and sit them up again. The Apple gets harder as the child gets older but you are also less likely to recline an older child. Think about how well the Cameleon storage bag would work for you. It is very hard to access in carrycot mode and if like me, you leave things in it, then it adds bulk to the fold. But ultimately either one would be a pretty good choice.