I love my manduca. I have used it for both my boys (and am still using it). It's by far the best baby purchase I have made. It doesn't hurt my back or shoulders (and my boys are quite sturdy) and it's so easy to use. Easy enough to strap bub in for a quick trip to the shop or even around the house if they are fussy and want to be held but you want hands free to do things.
I took it on the plane (we only did a short trip up north) but it was handy for strapping DS1 into (he was about 7 months at the time) around the airport and for getting on and off the plane. Will be taking it on our next holiday in a few months to use with Ds2.