We've used the high lift for everything from simple tire changing to winching and it is a good all-around tool. I would say a "must have" for 4-wheeling. With that thought, however, I also need to say that it is not a cure-all. They can be dangerous when jacking tall trucks (tend to like to scoot out from under the truck when they get past 2/3 of the way up - so brace things and take care), they also tend to sink into the ground - even hot blacktop, so a modified base is a good idea.
I have made a few accessories (and modifications) for my own jack that are really simple. First, I took out the cotter pin that holds the base to the jack and replaced it with a bolt. That made it more stable, as I can tighten the bolt to hold the base in place where I want it. Next, I made a chain attachment for the jack. I got a piece of tempered chain about 18" long, and a selection of screw-together links, a couple different style hooks (open and closed) and a pair of small clevises. That allows me to pull with the jack by hooking the chain, via clevis to the top end of the jack and another chain or a tow strap to the jack part with one of the D-rings and you can winch a truck by jacking up. I can also grab under a body panel to straighten it out, or even grab under a truck that is hung up on something by hooking the chain to the frame underneath. Third, I made a base for the jack. I took a piece of 12x12 diamond plate (diamonds down for traction) and welded a couple pins to it to fit the holes in the foot of the jack. I just put the jack over the pins - drop in a small bent pin to hold it and I have a solid base for dirt or soft blacktop. Makes the jack way more solid.
As for winches, Warn is best for a reason, but also more costly. Other manufacturers are great as well and often more reasonablly priced. I have actually looked at the Harbor Freight winch and know a couple people that are using them. They look almost exactly like the Mile Marker product. It wouldn't suprise me to discover that they were made in the same factory... The main difference is that the motor horse power is less on the Harbor Freight model. At the current sale price of 299 it would be hard to get a better deal (cost wise) in an 8000 pound winch. You can also pick up a no-questions-asked replacement warranty for 2 years on this thing - making it a pretty good deal I think.
Now, if you are dealing with a competition scenario - stay to the best you can get, but for someone still asking questions about high-lifts, you are probably just a trail rider advocate and a lesser quality product may suffice. Anything - even a come-a-long, that will extracate you from that occaisonal bad spot will be a godsend on the trail...