I use a hotsling pouch with 2.5 y.o. DD. It's easy to get on/off in/out. I mostly hip carry, but can easily slide her around to my back if I'm cooking dinner or something where I don't want her reaching in front of me. I don't do a back carry for extended periods, though.
I have a Beco, but she refuses to ride in it, and it's a lot of trouble to get her all harnessed up in it when she typically wants to get up and down a lot.