I may not have the quote quite right, but I think it was Churchill who said the Bjorn is the worst baby carrier we have, except for all the rest.
If you're wedded to the Bjorn, but you have real issues with the original, solid navy blue fabric, check out Baby Bella Maya's "Designer Front Pack Covers."
BBM makes fitted fabric slipcovers for most front-worn carriers, including the Bjorn and the Snugli. Most of the fabrics are a total chickfest, with satiny brocades and floral prints. But there's also one token cover for dads--and of course, it's camo. If you want a solid fabric, all you have to do is reverse the BBM cover. Or take it off.
Buy a camouflage Baby Bella Maya cover for $40. [babybellamaya.com]
Oh good, something to make a Bjorn even more sweat-inducing-- another layer of fabric!
You must check out the Kelty Kangaroo. I tired on the Bjorn and it made me claustrophobic even without kid... the Kangaroo worked great until he was ready for other methods of locomotion...
There are tons of really great carriers out there - the Bjorn is really horrible for all sorts of reasons. Kozy Carrier is my favorite. The Sutemi Pack is my second favorite, but it's more structured (has plastic buckle thingies) so maybe dads might like it better? The Kozy is my husband's favorite too; he won't even try ON any other carriers I bring in the house.