My $.02 worth...
I live in south Louisiana. The summers here are mid to high 90's and 70-90 % humidity all the time, so heat management is critical to me as I ride pretty much all the time. Due to the humidity, none of the evaporative cooling vests work here, and you end up wet and hot.
Like a lot of us, I have tried a bunch of stuff, including the LD comfort stuff. It works ok for me but as noted, the fly leaves a lot to be desired, and the compression fit is a bit uncomfortable for me, so the search continued.
A lot of companies make synthetic "boxer brief" style underwear. Some works great, some have a very unusual fit that tends to not work well and will ball up in unfortunate places, if you get my drift. Most of them are expensive to boot.
Then, I ran across the Duluth Trading "Buck Naked Boxer Briefs". These are wonderfully comfortable and pack very compact in any luggage. Highly recommended, and the price is very reasonable as is all their clothing:
I also landed on Coolmax shirts for the heat, and after a bit of searching ran across this site for all my T-shirts and such. The owner is also a Veteran, so even better to support him:
Final bit of the heat control and comfort is the Kontour seat. Best investment you will ever make on your bike. Comments and photos here: