I purchased a tug for our Glasair Sportsman... It's an older Aero-Tow model similar to their current Get-Jet which lifts the nose wheel off the ground. I made the purchase because moving the tricycle-gear aircraft backwards up an incline into the hangar, and over asphalt which frost heaves and often has a two or three inch "step" was nearly impossible without two people helping to push the airplane.
Fast forward a year or so post purchase. The lesson's I've learned are as follows:
1) support for the product from Aero-Tow is simply incredible. I did something stupid and popped the motor controller. Terry at Aero-Tow supported me like I had purchased the tug from him yesterday rather than it being a long-discontinued product owned by third- or fourth-hand owner. As a guy who spent his working life providing customer service I take my hat off to Terry for a job very well done!
2) my mental model of the benefits of placing the nose wheel weight over the drive wheels was right on the money. Traction is excellent, including on glare ice last winter. I tossed out a couple of soup cans of grit onto the ice where the tugs wheels would pass and the airplane was moved with absolutely zero concern for loss of traction. If building a tug, having it support the weight of the nose wheel over its drive wheels is an excellent idea. (The homebrew tug featured in the video linked in the post above works this way - it's just a great idea to let the weight of the airplane work for you rather than against you.)
3) the motor controller supplied by Aero-Tow features a significant speed differential between "pulling" and "pushing" the airplane. In fact I think it pushes the airplane at about half the speed available in "pull" mode. At first I didn't like this feature but now realize this is in fact an excellent safety feature. If building a tug, please give consideration to limiting the speed at which it can push. As most of us "nose wheel drivers" have discovered, pushing an aircraft equipped with a castoring nose wheel back into a hangar is a far more delicate exercise than dragging it out nose-first. Given that extra delicacy required in pushing the airplane back into the hangar, reduced travel speed is a really, really good idea.
4) the Aero-Tow tug uses a simple 12VDC ATV strap winch to haul the aircraft up onto a teetering treadle. The aircraft is pulled up to a hard stop block and held in place by the winch. The winch connects to the standard towbar attachment point on the nose wheel. For a homebuilt tug this mechanism may be easier to accomplish than the linear actuator-driven "chock" system shown in the video linked in the post above.
5) if you have a good tug, beware your hangar neighbors! They will all be envious and will want to borrow your tug. Don't let them, otherwise you may never see your tug again!