You'll find as I have that steel is fairly good at reducing problems with condensation since steel is a fair to poor conductor of heat energy = Less thermal soak. This tendency to not want to transfer heat in or out actually works out and it will take sometime before the pot starts icing up on the outside of the tube itself.
Bad news is a steel tubed pot will eat DICE since the steel is also harder to cool down in the first place but that's an acceptable tradeoff - The base itself is really what matters here.
As for the extra weight hurting the board, well...... that depends on HOW you setup it's mounting.
Doing a typical mount isn't the smart move with the extra weight to hold in place using your PCB as what it's all mounted to. If the mounting contact point on the pot itself is higher, that will make things easier inspite of the increased weight. Think of the pot's base as a fulcrum with the top of the pot as the end of a lever handle. The higher you can get the mount's contact point on the pot, the more control you'll have to handle the pot's additional mass without having to worry as much about the torquing effect on the PCB itself. The extra weight itself related to straight up or down to the CPU and board itself isn't the problem, torquing is and will rip the CPU area of the board right out if not done right.
Here's a shot of my steel tubed pot and you can see how I made the contact point of the mount higher on the tube itself rather than it being right at the base as you'd normally see with pots. This pot is about 15 inches tall with a thinwall steel tube and a 3/4 aluminum base.
Also helps to use washers at the board itself to help distribute the load stress over a wider area than simply at the mounting holes themselves, use them both front and back and you should be OK. Of course if you get too rough handling the setup you'll break it anyway so be careful when moving it around once the pot is in place. So far my setup has been trouble free and the pot once mounted stays exactly where it's supposed to.
I know you'll see alot of pots with the mounting point up high and that's why with steel it's even more important to have it that way, to control the extra mass without having torquing problems, especially if the tube itself is really tall like mine.
Edited by Kryton - 9/27/12 at 3:31am