Very old thread. But I figured I'd post my long-term experience with CTEK.
I've had 2 CTEK MULTI US 7000 for a long time. Also have a 3.5-amp model that's older but I never use it anymore (still works, just no need for it).
The first is treated decently. It's on the ground in the barn for the tractor. That plus the block heater are life savers in Michigan winters.
I have been very unkind to the second CTEK MULTI US 7000. It has been outdoors (uncovered) in Michigan for 8 years now. It's running about 7 months of the year full-time and 5 months part-time. 100F, -20F, ice, snow, rain.
It has scar marks from the time it got sucked into the auger of my tractor-mounted snow thrower (that sucked, the cord got wrapped around the auger and broke not only the auger shear bolts but the main Lovejoy coupling).
The wire insulation has faded a bit from sun exposure. There's mildew on the part of the cord that doesn't get much sunlight.
I once thought someone had stolen it after an ice storm and some snow. It turned out that it was literally under ice at the edge of the driveway where 4 to 5 inches of ice had accumulated. I found it humorous that I could see LEDs glowing and read the top panel through 2" of ice. Michigan winter humor, I guess. I left it under the ice. That was at least 5 years ago.
I had been using battery tenders for maintaining batteries in the garage, but the ones I had were useless for leaving outdoors (open vents, metal housing).
The CTEK MULTI US 7000 that I've brutalized still works flawlessly. It's been through hell and just keeps working. If they're still built the way they were back when I bought mine, I highly recommend them. One of those products I've been really happy to own.
My only complaint is that they need to be checked after a power outage; they don't remember what they were doing, and hence will stop charging if power is interrupted (sometimes with an error, sometimes powers up in 'OFF' mode). I don't know if that has changed in the newer models. It's the one thing I miss about the ancient no-smarts-onboard float chargers.
Found this thread because I'm looking to buy a third smart charger and hadn't seen the NOCO before. I'll likely but another CTEK due to familiarity and my experience with the older ones I own. But it's good to see some competition here, and from a U.S. based company.