I've got an Oregon splitter with the Kohler SH395 engine. It works fine. The engine starts up easily and runs well. Parts like air filters are a little expensive, but they are readily available.
Much of the wood I have is difficult to split. Bay and tan oak are both stringy and you have to drive the wedge all the way through the piece. Live oak and Eucalyptus are super dense. I tried splitting Eucalyptus by hand- an 8lb maul just bounces off. My criteria for a splitter is that it has to split the Euc and Bay. The Oregon "28 ton" splitter with 4.5" cylinder does it well. (splitter ton ratings are often wildly inflated. Calculating with the piston diameter and relief pressure, this one is not too far off).
Having used one for a few years, I'm not a fan of horizontal/vertical splitters. I find vertical mode to be useless. It takes a lot of upper body strength to position a round in the splitter. I'd rather use my much stronger legs and back to lift a round onto a horizontal splitter. When the rounds are too big to lift I section them by noodling with the saw. The H/V design has the wheels in the way of the operator, which is a bit of a pain but I can work around it.
I'd like to fab a log lift but the geometry of the H/V splitter with the wheels in the way makes it difficult. I'd love a push through splitter with log lift but I can't justify $6k+ for one.