I have a Heatmor and love it. Its 21 years old and all I have done to it is replace the blower at I believe year 16 and the door hoses (a very cheap fix) I think twice. I have never had a leak. That being said, the new ones are so different that I am not sure that my experience is really relevant. I would likely stick with Heatmor because it has been so good and Would hope that that would transfer into the newer technology.
I disagree with Ohioboy about having it made with steel you can weld on. I think having a stove made with quality stainless steel is important. The stainless holds up much better. Plus I have never heard of anyone really successfully fixing a leaking stove, even if it is easily weldable steel. WHY? because when it gets to the point that it starts leaking it is usually on the verge of leaking in many more places. You can weld up the current leak but there is almost always another spot ready to burst. It becomes a frustrating game of whack a mole. If the stoves get to a advanced age and start to leak you are better off replacing them than chasing never ending problems.
I agree with it's going to keep leaking and on the stainless.dont know how big a difference it makes but the reason I went with woodmaster is that it's round firebox and water jacket compared to others that had square ones with more welds where it would likely rust first but on stainless it shouldn't be much of a problem.