I have a lot of experience with them. I found them to be of excellent quality and design. I designed some into plants as long as 20 years ago and they have had no unusual troubles. Some field technicians do not appreciate the compact (8" high) starter buckets for small motors. Then again most manufacturers are going that way now anyway, and it is an economic tradeoff done at selection time. On plants where I knew this was going to be an issue, I simply required a minimum 12" high bucket and they complied.
Their circuit breakers used to have clear covers, which I always liked because I could inspect the contacts. I had a few electricians who didn't like it because they thought it was "wierd" to see the breaker mechanism work. I never understood that sentiment. I am not sure it that is the case any longer, I think Moeller may have succumbed to the pressure to be like everyone else.
The contactors are probably better than most IEC styles, but there again, most are now very good anyway IMHO. Years ago there were some cheap crappy IEC products spit out by small companies and peddled in the US by the likes of Westinghouse, but I think they did it on purpose to highlight how much better their NEMA contactors were. KM was never one of those, they always took the high road of quality and reliability. At one time they published a guarantee that if their contactors wore out prematurely they would replace them for free. I don't know if that is still the case but hey, it is worth asking. The trick is in the selection. If you have a load that has a high duty cycle or long acceleration, make sure you tell them that up front. Theur normal duty cycle was published at 1 million electrical operations (10 million mechanical). 1 million operations is 10+/hr, 24/7/365 for 10 years. I never bought any replacement contacts in the years that I used their gear on projects.
That brings up the main difference between NEMA and IEC design philosophy. IEC requires a little bit of application engineering, NEMA assumes the worst case so you don't need to think about it as much. You can always order an IEC contactor to match a NEMA rating anyway, you will just have to pay the higher price, as you do with NEMA design contactrs. Again, it is an economic choice.
I say if they are offerring a good value and you feel confident in their support, go for it. There is no lack of quality or short cuts taken in their design and manufacturing. The only problem is in that they are not as ubiquitous here in the US as say Allen Bradley or Cutler Hammer. If you have one of their offices close by, no problem. If you are in the middle of nowhere you may have difficulty obtaining replacements or add-on units off the shelf, but with next-day air and instant communications, that is not as much of an issue any longer.
"Venditori de oleum-vipera non vigere excordis populi"
