pani leica? Is it better than the 20mm 1.7? Is it on the pricey side : ( I know it seems weird. Good quality for low prices. Lolz, will consider it. Isn't the Sigma 16mm 1.4 just as good or better? It's in my price bracket : )
If price is a consideration, the 20mm Panasonic should be close to the top of the list. The 1st generation or Mark 1 is often available more cheaply and, having used and owned both, I think it's every bit as good as the Mark II. And the lens is a tiny wonder: a true pancake lens which, mated with a small mu43 body, gets you almost into the semi-pocketable range.
The PL15 is a different animal. Slightly wider - physically almost twice as large (though, honestly, relatively speaking, it's still a very small and quite compact lens) and... now one gets into the realm of things that are hard to quantify. But... it may be the single best micro four thirds lens I've ever owned or used. Period.
When I bought my slightly used one, years ago, I couldn't honestly afford the prices that even the used ones were selling for - but I saved a few bucks by buying its clone, the DJI-branded and 100% identical version of the lens, which Panasonic manufactured for DJI drones. Why, you are wondering, would Panasonic do this? Because (sssshhhh, don't tell anyone) Leica has (or at least used to have) a number of complex marketing, manufacturing, and technology-sharing agreements with DJI - and as a result of which, they asked Panasonic to make a DJI-branded version of the lens for DJI. The one I found at the time was significantly cheaper - but, ironically, that may no longer be the case (since DJI has acquired the status of a premier drone-optical maker).
Both the 20mm and the 15mm are superb lenses.
The 20mm is obviously closer to the classic 50mm FOV - while the 15 is perched in between two classic FOV's, the 28mm and the 35mm. So each gives you a different view of the world. But, honestly, both are amazing lenses.