I agree with the "buy what you like" philosophy. Not to get sappy but, every knife purchase is a step in ones journey of discovery regarding ones taste in knives, ones need for knives, and ones judgement of quality.
In regards to "cheap" fixed-blades, I remember a thread on the subject a while ago, and one of the posters told the story of how he received a cheap fixed-blade from someone. He considered the knife to be total junk and decided that for fun he would take it out and torture it to the point of destruction. He beat the hell out of that cheap knife, did everything he could think of to break it, but the thing wouldn't break. Finally he stopped and said "Damn, this is actually a tough knife", and he decided to keep it as a user.
I myself have been surprised and impressed by cheap fixed-blades. I used to work construction, then owned my own contracting business, and I carried a fixed-blade on sites which I found very useful for a variety of tasks, especially inspecting old houses that I was going to renovate.
I started out carrying a $300 D2 steel semi-custom (Wilson Tactical 25) which I had been carrying for years, including at a previous shipping job, and I used that knife to cut a variety of construction related stuff, pry wood, hack into rotted beams, chop through ancient plaster, pry out old wall fixtures, etc, etc, and it worked great for these purposes. But then I decided I wanted to preserve that knife (we had been together a long time), and so I looked for something new, and cheaper, that would serve my needs.
I saw a knife pictured in a thread on this forum that appealed to me, a Master cutlery "Alpha Team" fixed-blade, found one on sale on Amazon for $8 (not a typo, 8 bucks), bought it, sharpened it up, and proceeded to put it to work. And to my surprise, despite being mystery steel, that cheap knife handled everything my $300 knife did without missing a step.
Sometimes cheap knives can surprise you.
In closing, I want to speak up in defense of United Cutlery, at least the United knife I own. A long time ago I bought a United boot knife, named "Under Cover" (model number UC26, long discontinued). I was looking for a tough, dependable boot knife with a thick blade (3/16") and strong tip. It was inexpensive, and I wanted to see what it could handle. With an icepick grip I pounded the tip of the blade 1/2" into a 2x12 several times, and each time pried it out side to side, I expected the tip to snap off, it didn't, nor did it bend in the slightest. Then I took the rubber handle off, laid the knife across two steel bars and pounded the center (where the blade meets the tang) with a one-hand sledge hammer, I expected the knife to break, it didn't, nor did it bend. I determined the knife was sufficiently tough, and I bought 3 more. This is not an endorsement of all United products, just my personal experience with one. That first knife is one of my most prized fixed-blades, and I carry it regularly when I go out at night on my own property.