Watch out for horsepower claims. Many of the companies have been sued, or are presentlty being sued for making false claims. Sears,John Deere, Briggs & Stratton, Toro, Kawasaki and Honda are being sued at present.
In regard to engines? If price is any indicator of quality - the cheapest 6.5 horse Briggs sells for $200. The cheapest Honda GX (commerical) 5.5 horse sells for $430. So, look closely as model number info on the engines when buying. The el-cheapo Honda 5.5 horse is the GC series instead of the GX.
One example of real horsepower. The Honda commercial-grade "5.5 horse" GX160 engine puts out a maximum of 4.8 horsepower at 3600 RPM. That's a bit shy of the 5.5 horsepower claim.
I don't have the Briggs specs. Best thing to do it go by engine quality and size (ccs or c.i.).
I'd want an engine that has ball bearings on both sides of the engine. It's important for HD work. Some of the Briggs do not - all the Honda GX do.
There's no work-around for cylinder-bore. The bigger the bore, the more splitting potential you're going to have. Now, if it's going to matter to you? It depends on the type of wood you split, I don't know. Also, the larger the cylinder bore, the bigger the hydraulic pump you need to keep the cycle time fast. And subsequently, that calls for more horsepower.
I've got three log splitters. One with a 3 1/2" bore cylinder, one with a 4", and one with a 4 1/2". There have been times I wish I had a 5" cylinder. Yeah, you might be able to run a higher pressure, but that has limits.
I often get involved in taking large wood from power-line right-of-ways that nobody else wants to mess with because it's so big, heavy, hard to move, etc. It's usually red oak or hard maple. If you get working with 3 foot diameter hard maple wood, down near the bottom, a 4 1/2" splitter will have trouble splitting some of it, but that's rare.
For the majority of wood, even the 3 1/2" bore works okay. But, it ticks me off when I've taken the trouble of cutting large maple and then, can't split it. Pieces like that, I've had to rip with a chainsaw instead - and that's not easy with standard chipper chain. There is special ripping chain - but I don't own any.
So, other then wanting the capability to split anything, I guess comfort and fuel comsumption are the two major factors. And, maybe portability?
I've got two horizontal splitters on wheels, and on vertical that goes on the three point hitch of any one of my tractors. I never use the horizontals anymore. The vertical is much easier on my back - and big wood can be rolled to it - at ground level. That's a big plus. The control lever is also up high, which works better for me. I've had two back surgeries, a broken neck, and I have steel pins, plates, and screws in various parts of my. I.e., I'm a little beat up.
An other plus with the three-point hitch, is it's so easy to drive the splitter on site where a big tree has been felled and cut, if necessary.
On the subject of fuel consumption - that's one down side to putting a three-point splitter on a 30 plus horsepower tractor. The engine is oversized for the job, and thusly wastes some fuel. A good 10 horse gas engine is going to be cheaper to run - than a 30 horse diesel being underworked.
That all being said - I haven't used either of my self-powered splitters in years. I love the three-point hitch splitter. It's hooked to a large PTO hydrualic pump and I can stick it on any tractor I own.
In regard to engines, you can't go by the brand name. Briggs & Stratton, Honda, et. al. all make good HD engines as well as cheap crap. All goes by the specs when purchased. Subaru, Kawasaki, and a few Chinese companies also make some very good engines when bought right. Subaru has been one of the best on the market since they first came out years ago as "Wisconsin Robins", but they are pricey.
Troy-built is made by MTD.
