I researched and tried them all at Sears when we needed to buy a new machine. I got the X3 because it was $1000 cheaper than the Treadclimber and my wife has balance issues, so the two little peddles sucked and messed her up...
The incline trainer rocks...I just do the preset trails because Jillian's Workouts are too damn easy ~snickers~, but that 40% incline is uber sweet and will be nice to prepare for yet another backpacking season ~smiles~.
The new Xi7 if Wireless and has Google Earth Maps, so you can even do Everest if you wanted too ~chuckles~. It has a -6% Decline to 40% Incline...but we went for the X3 because it was the overall best value for the buck ~smiles~.
Everyone in the family uses it ~smiles~. So it takes a lickin' but I would still buy the in home maintenance and repair for 5 years ~smiles~.
The directions on both of them suck, albeit the Treadclimber direction are a bit better. The X3 took about 15 minutes to put together ~chuckles~...Treadclimber takes about an hour ~grins~
And I own a bunch of Bowflex stuff, so I am a loyal customer, but one thing I do know about bowflex is once they sell ya something they don't want it back and a 25% restock shelve fee is way too much for my blood, so make sure you get the right one ~smiles~.
Nice thing about iFit.com is you can custom make your own workout card if you are hardcore ~smiles~