I'm in Phoenix, where it is hot much of the time. And, I'm usually dressed in suits, business casual, etc. I carry concealed, and it
must be completely concealed.
I've been using Thunderwear for about 14 months, and generally like it. The only other options I see are a belly band (worn so the pistol / revolver would be under my left armpit - thus, a cross draw), or an ankle holster.
I've tried the belly band briefly, and while more accessible, it is too hot. I've passed so far on the ankle holster because ready access requires modifying my pants.
The Thunderwear gives me the ability to carry, but as noted above, it is slow. My last time out at our informal range, my buddy timed my draw - between 2 and 4 seconds. Too slow, really, for some situations. But, if we're talking about a restaurant or office where a commotion starts and I want to be able to defend myself and other innocents, it may very well be sufficient. And, in those rare cases where I've felt the potential for a problem existed, I've pulled the pistol up where it is more accessible.
I use a Kahr K9, and it fits fine. I tried a Paraordnance P-12 once, and it was too big - possible, but not really practical. Besides, I'm not keen on carrying a cocked and locked 1911 between my legs.
DAO seems a better action choice.
One other point. I wear it over the tails of my shirt in the front, but under the tails of the shirt in the back. That way, the elastic strap is not visible if / when the shirt rides up a little in back. And, the pistol rides below my belt line. If I was in better shape, perhaps I could keep the butt under my belt, and that would be better, IMHO.
I've tried imitations, and prefer the Thunderwear brand. And, they've treated me right ... I have the very clear impression that putting out a quality product matters to them. Consider the 'Federal' model with the extra compartment (two in front, and another hidden behind them) - can be handy for carrying a second mag, cash and ID, etc.
Good luck. IMHO, this is one of those things you just have to try. Gamble a little money on this, and find what works for you.
Regards from AZ