Here is MY experience with Triple 7, YMMV, starting with the good first. It does give additional fps, even over Swiss, using the same volume loads. I shoot over chronographs frequently, using various powders, real black and subs, and Triple 7 is the fastest. It seems to be very accurate, especially in revolvers, and I credit this to substantially reduced fouling. Triple 7 does clean quite easily, much more so than real black, and even more so than Pyro. Triple 7 is readily available most of the time.
Now the bad. It is expensive compared to Pyrodex, almost double the price in my area ($21 vs. $37 per. lb.). Real black, after paying hazmat fees, is almost as expensive as Triple 7. In revolvers using Triple 7, I have had zero issues in thousands of shots fired with ignition. However, in sidelocks, even those without a patent breech, I get hangfires after a few shots. That is remedied by a quick cleaning, then I am able to get several more shots before delayed ignition begins again. This is something I have never experienced with Pyro or real black.
Here are MY conclusions on Triple 7 use compared to other powders. Fast, clean and accurate. While I do get more fps, it has a lot more variance in fps, shot to shot compared to real black (Swiss or goex) with which I get remarkablely low extreme spreads. When I go hunting with a sidelock, I use Swiss to maximize my chance of going bang. I give up fps, which I could make up with more powder, to ensure reliable ignition. I have used pyrodex for 45 years, and it is harder to clean, but I have 4 decade year old barrels that have shot a lot of Pyro, and they look as good today as they did in the 70's and 80's. I really have no complaints with Pyro, and used it exclusively for many years (before my flintlock days) as before the internet, I just thought it was black powder. Just for info, Pyro P and Swiss 3f give identical velocities in every gun I have ever shot them both in, and Goex is lagging substantially behind. Not a complaint, just a fact of many thousands of rounds over a chrono. I am not against any powder, I shoot a lot of all of it. I use Triple 7 a lot in revolvers, but when my current supply is gone, I will not replace it due to cost, unless it is the only option available. If I am really earnest about making sure a gun goes off, I load with Swiss, even though I have had no issues with Pyro in caplocks. Sorry to ramble so long, just MY experiences.