Personally, I dont see a lot of difference in most of the homeowner machines, You get what you pay for and with proper maintenance, they all will last a pretty long time. Like everyone else, I do have my preferences as to what I want out of a splitter. I have my likes and dislikes between the vertical and horizontal, wedge on ram and wedge on beam designs. With a vertical splitter, the wedge pretty much has to be ram mounted and it works pretty good, but here are my exceptions. In vertical mode, I dont have to lift a heavy round to the beam, but I still have to bend over and turn and twist the round until its split to size. I also have to throw every split out of the way as I go and before I can make the next split. The short wedge usually means a big stringy round doesnt split clean and I end up twisting the full round to whittle it down to size. Even sitting on a stool, It just plain wears me out. In horizonal mode, it gets better, but I find the height is to high for me and I have to lift that big round to put it on the wedge. The plus is that with a log cradle, the half splits are laying within reach for resplitting and you dont have to keep bending over to pick up pieces for resplits, sort of.
A horizonal splitter with wedge on beam is my preference, but this too has some disadvantages. You do have to lift every round to place on the beam. When a big round needs resplitting, well the ram just pushed it off the end of the beam. If you have a log cradle at the end of the beam, you have to reach out and drag the big pieces back and if you dont have a log cradle, you have to walk around and pick up the piece and put back on the beam to resplit. The advantage of wedge on beam is if you use a multi split wedge and are splitting decent size wood that doesnt need a lot of resplitting, its very easy to back a trailer under the beam and let the splitter just push the splits onto the trailer as you split. Its also very easy to put a conveyor at the end of splitter to carry the splits out of the way, or load in a trailer or truck.
No one size fits all, Even commercial models dont fit everybodies needs and is why so you see so many people doing modifications to new machines they just bought. To me a perfect splitter would be one I load with rounds and I dont have to handle those rounds again until its time to stack. Aint seen one of those yet, and if Ii do I will then start looking for a automatic stacker. Never satisfied.