Saram, Nothing is comfortable to go vaccuuming in.... Vaccuuming just isn't meant to be comfortable, I think

Nadine, I think whichever fabric or carrier you end up buying, you will get warm. Most of the heat comes form the close contact between you and your bub. If you do end up going for a mesh type material, there are 3 things to think of: first, make sure it isn't a loose mesh where little fingers could get trapped. It's not the end of the world, but could prove annoying. Secondly, again, about how tight the mesh is. cause some meshes can really dig into your or bubs skin. Ever tried to sit on one of those mesh type office chairs in a mini skirt? It hurts after a while. So make sure it is a nice soft fabric with a small holes. And lastly, Even if it is a mesh, if it is fully "plastic", it could still get sticky. Some man made products actually have fantastic breathing qualities, but others don't.

Now about ring slings, I know some women swear by them. But I personally prefer wraps or Mei Tais (although I've never used a MT) as they are worn over both shoulders and they pull bub really close to your centre of gravity which makes it very comfortable in the long run. Slings that go over only one shoulder just don't really feel all that comfortable in the long run, to me. Alright for a quick trip to the shops, but not for long term wearing.

If you do decide on a MT, then I think (from other people's feedback) going wiht one that has slightly padded or very wide straps might make them more comfortable.

Just my personal opinion.

Sasa