Feature to look for (as we discovered whilst testing them in the Lake District) is a rain cover…and how quick/easy it is to apply.
Some come with a shower cover but a full rain cover totally covers the child…(other option is just sticking child in and out of waterproofs). We tried the Mac Pac and thought the RainCover was awkward…ended up with a Deuter Kidi Comfort 3 + additional rain cover…it's a good pack, good amount of storage / adjustments / has a sleeve for a drinking bladder…only downside is that as it has a metal frame it can squeek a bit (did when new although I think it has 'worn in' a bit now).
We tried loads…even the botton-of-range Vaude and Deuter are pretty good…things that put me off others were rough (but pretty) animal patches on the chin pillow just where little might be resting their head…and also clips for rain-covers again just where little one could be resting their head.
Kick-stand is (a little bit) handy but you should never leave it free-standing once nipper is in…some of the others without the stand will still stand upright anyhow so maybe not a big deal.
phew !