Two Questions
How much wood do you split a year?
Do you need the log lift and hydraulic wedge?
When I was looking around a couple years ago, I was torn between the TW-5 and TW-2HD. I settled on the TW-2HD. My reasons, I did not need or want the log lift as it forces you to work primarily on one side of the machine, plus when I demoed a TW-5 I kept tripping over the log lift.
The hydraulic wedge lift was nice but I can install one on my TW2-HD for around $200 much less than the factory wanted. I have found the 2 standard heights of the 4-way meet my requirements. One height for large splits for OWB / IWB wood and the lower setting for stove wood splits. If you are certain that you want to try and run a 6-way wedge then the TW-5 is the only choice between the two models.
Having had a TW-P1 prior to getting this splitter I was very confident I really did not need a 5 inch cylinder for 90% of what I split. I do like having the hitch opposite the wedge. The clearance of the large tires and wheels were a must as I have to get the splitter into some pretty rough landings and this was a problem with the TW-P1. The TW-5 and TW-2HD use the same outfeed grate and are built on the same frame.
As to price, I bought the TW-2HD for about $4800 out the door with auto-cycle, 4 Way and outfeed grate.
Talk to the dealer(s) in your area. The better dealers will almost always either have or make arrangements for getting you, a demo machine for a day or two.
Food for thought.
Take Care