I got a Mei Tai and DD and I love it!!!! It fits all of your criteria although my DD is only 6 months old so don't know about carrying a toddler in it as yet. Good luck with your search, I spent ages trying to find the right carrier for me and now have another two I don't use. It really does come down to personal preference so maybe you can try some on in shops before you buy? Also have a look at babywearer dot com I found it really helpful for weighing the pros and cons of each carrier/sling.