I've been using the HF changers since 2005 (first one was lost when my house burned in 2007; bought another one a few months after the fire). In all, between my neighbor and other riding buddies we've changed close to 200 tires on the two machines. IMO for the price they cannot be beat.
Yes, they do require some mods. The bar that comes with them is only good for leverage on the bead breaker. I bought the No-Mar bar with the first machine, but got the Mojo Lever (a copy of the Coats bar I think) for the one I have now. The Mojo is much better IMO. Never a pinched tube or scratched rim.
The other main mod I"ve added is three nylon do-hickeys that replace the stock steel mounting points (also to protect rims). These I got from the Mojo guy (don't remember his name right now, sorry).
I think I bought the HF machine on sale the last time and it was a total of about $50 with the motorcycle adapter. The Mojo lever was around $100 and the replacement nylon wheel mounts were about $15 (I think). I also bought the Marc Parnes static wheel balancer for around $100. So, in all, I"ve got around $270 in the entire tire-changing/balancing setup. It paid for itself about the second time we used it!
My neighbor and I both have 950 KTMs ("Kills Tires Monthly") and we each have other DS bikes that seem to go through tires like a dose of salts thru a widow-woman, so the machine seldom is idle more than a week or two. Plus, several other riding buddies also come by at tire-change time.
If I had plenty of money to spend I could justify paying for a nicer machine with the number of tires we do, but the old HF machine works just fine and I know its ins and outs. Maybe if I can ever break it...