I've really never had any major issues with my CTX3030 and I have really put it through the rounds in every conceivable torture test. It's been bounced around in the car, dropped countless times, run in temperatures ranging from around -30 up to 110, fields, woods, and underwater. The only thing is the interface to hook up wired headphones from the waterproof jack doesn't work, which had problems since I bought the machine used, and then the cam lock on the shaft wearing out as is a well known problem and easily fixed with a zip tie.
As for other products, my 705 has also been used a lot without issue, and the GPX4800 worked wonders at the beach in Florida without fail.
I use all 3 machines with many coils and haven't had a single problem-unless you count wearing out skid plates. I'll certainly stick to my Minelab products!