Wife sponsored tools are a good thing!
I'd get the splitter. You will not look back! You do have a good wife there. She sees the value in: you, burning wood,..........
You're doing good asking questions here and have gotten some good advice from others! I'll try to add to it.
Be sure to look at cycle time. Watching the ram move is like watching paint dry. Does your wife help with the wood? Maybe she can run the splitter esp. with the next suggestion.
Either get a log lift or one with the option to tilt and run vertically to help with those large hunks. There are advantages to both. If you get the tilt option, the wedge will be on the ram and the split wood will stay with the splitter and you don't have to pick up the larger chunks to split again. Having the wedge on the beam allows the split wood to be pushed away for someone else to pick up and stack. You'll open up your options to get the larger wood by not turning down the "unsplittable" stuff.
Another good option is to be able to raise it up to a comfortable working height. My FIL is a big tall man who doesn't like to bend down. When he does bend down he looks for other things to do when he's down there.
Anyway, what we've found that works well for lifting the splitter to a better working height is to use auto ramps to run the splitter up on. Then we just leave it connected to the pulling vehicle.
How far does your dad live from you? If there is some distance, you also might want to consider larger tires and a wider axle so you can transport it without it flipping all over the place.
Do you have a place to store it inside?
Make sure the stroke length will cover the length of wood you want to put in your OWB.
A drop on four way wedge is nice too. It cuts down on the number of times the ram has to move.
Another thing to consider is an electric one which are quieter. If you're going to be splitting where you have access to power that is. However, make sure if you do get an electric one make sure it will do the job and not stopping on the tougher ones.
If you go with gas, consider getting one with an engine that has: low oil shut down, pressure lube, idle down between splits, ........
A large engine with a high volume pump is fast and powerful. However, that adds $$s and takes more fuel and adds weight to the machine.
Just remembered SpeeCo splitters who have an add at the top of this page. I believe that they have a "power" stage that will go through just about anything but give you the faster cycle times on the easier stuff.
Regards
Dan