While you've got a point with banana, ExBrightonBell, I actually think Ella's might work out cheaper than fresh fruit for things such as mango. Not that the pouches are in any way better than fresh fruit, of course, but I don't think they always work out far more expensive - not with the price of "exotic" fruits as it is.
Fruit-wise, I tend to buy the frozen bags of berries and blitz those up to add to porridge etc. They work out much cheaper than buying fresh blueberries, raspberries and strawberries separately, and obviously keep longer. Apples, pears, bananas etc, obviously I buy fresh
I quite like Ella's Kitchen. They're really convenient for when we're out and about, or when I haven't had chance to make something up for DS myself (I'm back at work full time and, some days, it just doesn't happen). I quite like the Hipp Organic pouches too.
MIL bought DS some of the Heinz ones, and they're utterly grim compared to Ella's. At least Ella's and Hipp generally taste like what they're meant to. With the Heinz ones, DH and I did a taste test and couldn't taste the difference between the "chicken" and the "fish." Bleeuuuugh.
Anyway, back to the OP. I think Ella's must be 0 per cent other stuff, as I doubt they'd get away with lying on the packaging. At least I hope they're as "pure" as they claim, I don't need anything else to feel guilty about!