I believe the quality of construction and components is the big difference between the entry level products and the top of the line products and i believe the difference is very clear when you put hands on. Me personally, I prefer Millennium and Hawk. In my opinion, they're two of the best-built and most comfortable stands on the market. i haven't tried one in many years but I'm liking what I'm hearing on some of the new Rivers Edge ladder stands.
I also consider intended use when purchasing a ladder stand. If I'm going to bow hunt out of it, I prefer a 1.5 man stand size and the platform must be one that goes all the under the seat back to the tree and the seat has to be able to be folded (and held) up, back towards the tree. I'm less concerned about that when it comes to rifle hunting unless it's a spot where I might bring a new hunter or my son. Then, I'll look for a 2-man ladder stand and again, look for one where the platform goes back to the tree.
In the end, you get what you pay for. For me, being 16'-20'+ in the air, I want the best built stand under me that I can afford. There are many things we can cut corners on to save some money but there are some things we should never compromise on when it comes to safety just to save a couple dollars.