A lot of this is going to depend on where you live and what companies you have near you. Especially if you're not going to do the trailer adjustment (to properly fit your boat) yourself. There is, however, a difference from one manufacturer to another - not just in the frame, but also the smaller components. If you're planning on using this trailer for more than something for the boat to just sit on, don't make your decision based on price alone. For example, Venture is a very low end trailer and quality control has been very much hit or miss. The last thing you want is to save $ just to spend $$$.
You can see my location in my signature - near me, I have Tidwater which is a solid, entry level trailer. Shoreland'r is a higher end trailer. Load Rite is OK. I've heard others mention Owens and Sons, but I'm not sure where they're based out of or if they have an extensive dealer network.
Check your state's restrictions - many states require brakes on both axles.