I have a pretty strong fear of heights and what I can say that the stand doesn't matter too much but the SAFETY STRAP is where confidence comes in. I bought a new Muddy Outdoors safety strap this year and it makes me feel more secure than ever in a tree.
Stands can help a little bit if you get one that you see has solid construction, good tree bite, and (what I like) a big foot platform and seat that has a full wrap around bar ( not just a seat with open front). I currently use an Ol' Man Grand Vision. Also, I have NEVER found a reason to climb over 20 ft in a tree. Just note, the further you go up, the weaker the tree gets (smaller diameter with added 150-300 lbs on one side or the other). I've known people that went 30-40 ft up in a tree and it started to bend/break.
Some generall tips to help your fear:
1. Practice. Practice. Practice. Start by attaching your stand to the tree and then going to 6-8 ft (do it a few times, start to finish). Then redo it and go to 10-12 feet. Then finally repeat it going to 15-20 feet.
2. Even while standing on the ground, place your safety strap at appropraite height (above eye level) and try to sit on the ground. If your strap is adjusted right, you shouldn't be able to sit down. However, you will hang a few inches to a foot off the ground. Try this again but with more of a quick falling action. Your strap should easily hold you up or dramatically slow your descent.
3. My biggest fear is that something will malfunction with my stand or my strap because of my bad luck and common forgetfulness. However, practicing like I describe lets me get used to setting up my stand, getting comfortable with moving around in it while its on a tree, and enforces my confidence in my equipment. Knowing that I have a good/reliable stand, a very secure safety strap, and knowledge that I've done it over and over again without trouble.
Best of luck