Regarding the LL libs..
There's no way in a very warm place I'll even attempt to use that.
If it's just the lower parts of the HAL, it _will_ suck, as the HAL was, by far, the buggiest vendor-library I've had the misfortune of trying to use in production..
I'll keep using StdPeriph for all the chips that it works on, and bang on the hardware directly for the chips where it doesn't..
Sure StdPeriph isn't ideal (functionality differs between STM32 chip families), but it does work.
I really like working with the STM32 chips (heck, see my nick on the forum), but somehow I find myself using them less and less these days.. They simply don't fit my designs any more. And, it's not because of software. There's no integrated RF connectivity, very high cost, and can't go low enough in power-consumption (for most of the STM32s).
The designs where I used to use the STM32s in were projects where you needed a beefy MCU to drive a display or similar. However, for the price of (for example) an STM32F429, I can easily get a Cortex-A7+RAM+PMIC these days.. Sure, larger footprint, but usually not an issue if you have a design with a display in it.
For low-power stuff, with small footprint, ST is at least one generation behind people like Silicon Labs EFM32, Nordic Semi and Dialog. Nordic and Dialog even have built-in radios... And, they're still cheaper than the low-power variants of STM32s..