That's true - when we had the jug in our galley, it was September/October in Michigan - we had a few hot days, but nothing like Arizona-hot.
Before I found the jug, I was using two 64-oz Nalgene rectangular bottles that also fit very nicely under the sink. On the one warm campout we had this summer (we had a lousy summer), I didn't notice the bottles getting any hotter than the outside, ambient temperature:
http://www.rei.com/product/402058/nalgene-space-saver-bottle-64-fl-oz
Both the Nalgene container and the aloe vera jug are made from #2 plastic (HDPE: High-Density Polyethylene) which is considered one of the "safer" plastics. Of course, most laundry detergents also come packaged in #2 plastic....
The Nalgene bottle is definitely sold to be re-filled and it's much heavier construction than the jug. We use them to hold cold water in our fridge at home. The wide-mouth design makes it easier to fill from a spigot - and it pours out nice, too. I highly recommend them - they're pricey at $12 each, but if you've got some dividend dollars laying around unclaimed and you want to store some extra drinking water in your galley (that isn't in your fresh water tanks), they're very nice. You could also freeze them and use them in your cooler.
I like the jug because it was "free" with the purchase of $7-worth of aloe vera juice, the handle is very handy (ha!), and I can store one gallon in less containers, in less space. I suppose if you do drink aloe vera juice (or know someone who does) and happen to have a steady supply of containers, maybe switch them out periodically...if you're willing to risk drinking out of a compromised plastic container that's probably been sitting around in a warehouse somewhere under fluorescent lights for who knows how long...OK, never mind...I'm going to use stainless steel from now on.....
Here's a really cool double-wall stainless steel 1/2 gallon water bottle that we bought for use as a growler but none of the breweries around here will fill it because it doesn't have a Surgeon General's Warning and the cap can't be "sealed" to properly comply with state & local growler laws. It's a little too tall to fit under the sink but that's OK because you probably cram other stuff under there anyway. The cap has a little handle pull-thingy if that seems useful. It comes in the burly man (a.k.a. gender neutral) colors of brown, black, and classic stainless steel - it's $55 at REI but you can probably find it cheaper somewhere else:
http://www.rei.com/product/850811/hydro-flask-wide-mouth-vacuum-bottle-64-fl-oz
Yes, I bought mine with dividend-dollars. They really are nice and they even sell a straw-lid for those days you want to sit in your car and drink A LOT of water (or coffee, or apple pie, I don't judge) but you don't want to have to hoist up a 1/2 gallon jug, moonshiner-style:
http://www.rei.com/product/867473/hydro-flask-wide-mouth-lid-with-straw