I have a Nathan Vaporair that I like. For extended sessions I’ll carry two of their 18 oz bottles with concentrated Infinit in the two front pockets and fill up the bladder with water.
Vest:
https://www.nathansports.com/vaporair-men-s-hydration-backpack-4532n
Bottles:
https://www.nathansports.com/speeddraw-replacement-flask
For what it’s worth, UD, Nathan and Ultraspire were all founded by the same guy - when his time was up for whatever reason at each he moved on and founded a new hydration company (waiting for his no-compete to expire if applicable). They all have products that work well, and Solomon and Camelbak do now as well. Best bet might be to try something on in a store and see how it fits you, but there are a bunch of products that will all do just fine, as long as you take the time to adjust them to your body and pay attention to chafe points (lube, tape, whatever). The beauty of anything (bladder on the back, front bottles, handhelds, whatever) is that the more you drink, the lighter and more comfortable they get, so if your gear is bugging you, just drink more 
You won’t know whether you like rear bladder, front bottles (or rear bottles - Orange Mud) or handhelds until you have tried each, but a basic pack with 2L bladder is probably going to take care of you. If you do go with a bladder, given your climate, get some sort of insulated hose if you can, that helps when it’s hot otherwise your first swig is always pretty harsh. The alternative is to exhale back into the hose each time you are done drinking, to clear it and keep the fluid cooler in the main pack, but then you’ve got to pull through a bunch of air whenever you want more.
Thanks everyone! I the UD and nathan that everyone is recommending on order and going to just see which one feels more comfortable and send the other back. I’m pumped!