Pros: Frees up hands, outings last longer since child is no longer bored easily
Cons: If you have long hair, you must remember to move it before placing the child on your back...it is easy to get a few strands caught now and again
I wish we had this when my son was younger...instead we used the Baby Bjorn, which he hated because he couldn't see anything when facing me and couldn't see me when facing out! We purchased this after our last move (husband is in the Army, so we do that a lot), when my son was 13 months old. We love it! It fits him well (a six footer) as well as me (5'3"), due to it's adjustability. My son instantly enjoyed riding around in it, instead of a cart or stroller, where he gets bored easily.
We've used it hiking, shopping, etc., but most importantly, it was a lifesaver at the airport. Since I travel back to see family 2-3 times/year (mostly without my husband who is usually training or deployed), It frees up my hands to carry his car seat and a carry-on. All his things fit into his backpack that you can unhook from the carrier when storing it in the overhead bin. What else can I say? Oh, yeah...I cut my son's hair in it. Our high chair won't allow access to the back of his head, so one day I plopped him in his trail blazer, secured him, popped out the kickstand, and put on Blue's Clues. It worked! Now it isn't such a chore to cut his hair (which grows like a weed).
I will keep this thing forever. Ok, until we're done having kids. I am also excited to use it whenever we have another child from when they are younger...say, 3-4 months, when they aren't as needy and the Bjorn doesn't cut it anymore. We did have to replace one of the buckles (the one around the waist), but I think it was from overuse.
We never used our stroller from the day we got the trailblazer, until very recently. He is still ok to be carried around by his dad in it, but minimally by me because of his weight now at 20 months (I'd say he's about 28-30 lbs?). It is imperative that you make sure you follow directions on how to adjust for your height...most importantly, that you pull on the straps from the padding over your shoulders down and away from you like you are doing a tricep curl, until you feel the weight is distributed correctly.
Also, we have had an alteration to it on the shoulder pads where the straps are the whole width of the pad and on the outside. When it was in original form, the straps would "dig" in around the front of your armpits after hiking for a long period of time. We only did this because my husband had his own army rucksack altered this way and found it to be beneficial.