I've hired a mesh ergobaby adapt from a local sling library because we have a stretchy wrap but it's really warm and it will be horrible in the warmer weather (fingers crossed we haven't had it all yet) and on the tube but it's just not comfy for me the seat adjustment tabs dig in to my hips front carrying and the shoulder straps are too long and bulky when back carrying 
I borrowed a normal fabric ergo (it's softer) from a friend and that's better on my hips but the shoulders are still iffy and I think it will be too hot
I really like that the ergo doesn't drag all over the floor when taking it off or putting it on unlike the stretchy and it's much cooler.
I also tried either a Connecta or Integra - not sure which - but while it felt nice front carrying, was out because the straps dug in my boobs where the webbing was sewn when back carrying
. The woman at the library said my baby was in between sizes for the brand I didn't try atm so maybe I could try the bigger one for when she's bigger.
I'm starting to eye a ring sling in linen or something but I'll go back to the sling library and see what else they have to try.
Has anyone else had the hip problem with an ergo?
Which baby carriers do you like fore summer?