I have a KSGER bought a few months back (HW 3.10, SW 3.1S), after relying on Weller my whole life.
I haven't been "plagued" by anything except by some really annoying bits in the user interface -- specifically, you need to be really careful not to stray off the path when calibrating tips, because you can easily reset a perfectly good calibration by pushing the wrong button at the wrong time. A little brainpower is sufficient to work around this. (Something I hope for.)
The T12 tips you can get in sets for extraordinarily low money from eSomewhere were wasted money. Horrible. Some of them were immediately broken. But mostly, the fact that they require unique calibration for each tip is an indication that they're sloppy from the start. Hakko doesn't find it necessary to have separate calibration per tip, because they all work right. I bought T15 tips directly from Hakko online; they were the same prices as everyone else, shipping costs were reasonable, they showed up in two or three days, and I am confident they are not counterfeit (unlike some of those I might buy from eSomewhere). You can calibrate them all individually if you need a new hobby, but you can share calibration between tips if you like, and you should be in pretty good shape.
By the way, for calibrating, I bought one of those cheap imitation Hakko (blue and yellow) soldering iron tip calibrators from eSomewhere. I was very frustrated with it, for two reasons: one is that they covered the display with frosted plastic (which was easily and crudely removed with a sharp knife), and the other was that the temperatures were all over the map. I searched for reasonable techniques for cleaning the tips and the sensor, and different approaches to blobbing solder in all the right places, and it was still frustrating, with temperatures all over the map. So along with my Hakko tips, I ordered some Hakko sensors. Beauty. Completely solved the problem; the cheap meter worked just fine with them. I don't know if the even-cheaper white ones work also; I would guess yes.
The iron itself, the "handle", is quite mediocre and rather poorly made, but it works well enough. I had to go in and... I don't even remember what tweaking I did -- something related to how it held the tips in. I think I loosened it up somehow, using nothing more than common sense. I also trimmed off some sharp flash from the plastic molding that would cut into my hand. You don't get "elegant" for those prices! But if you try some times, you get what you need. If you're the kind of person who needs all the little perfections in order to get anything done, you're probably going to need more money. If the end goal is your goal, this one will be fine.