mmmmm weird. The ones I've got here are definately not shielded. If you just have them on the heat is neglectable. If you use them however, feel the top part of the cone. It gets hot. The bottom part stays cold.
I have heard other people say they don't make noise, but every single pair I've seen / heard does make noise.
Vox, the last album I mixed before I started building the new studio was Pete Bardens & Mick Fleetwood, which I did totally on a pair of Mackies. They are pretty decent. A bit sensitive to placement, but they have some very good template settings for that. Also, you have to be somewhat carefull with the volume, as the sound changes in character a bit when you push them. Saying that, definately no more, or less than, most others in their price range.
The LSR28's and the Quested 3208 are, as far as I'm concerned, by far the best self powered monitors available today, and very much ahead of everything else at that. I've just this week installed my new monitors, five LSR28 and one LSR 12. One of the key things with these monitors is that they are totally accurate at all volumes, the mixes translate very well, and you can work on them all day without your ears getting tired.