I want to know about the difference between "Ultra-Low-Power" and "Mainstream" MCU Nucleo's Series

[ADavi.3]

I would like to buy a microcontroller package and I am seeing the difference between the Nucleo-64 microcontrollers since they all have almost the same specifications but then I saw that there are 3 notable differences which are "Ultra-Low-Power", "Mainstream" and " Performance "so I can't decide between a low power or mainstream microcontroller

[ADavi.3]

Image Reference

[ADavi.3]

Reference

[Tesla DeLorean]

Any thoughts about what your application actually needs/requires?

Perhaps in terms of code space, RAM, speed, power sources, etc..

[ADavi.3]

They are for college projects like calculators and clocks on displays

[TDK]

They are all quite similar. Some are faster, some are cheaper, some are better at low power. The differences are subtle.

If you have no particular need in mind, perhaps use availability or popularity as a factor. STM32F4 has a ton of reference material online.

[Tesla DeLorean]

The 16KB code space of the L011 parts are a bit challenging/tight

I would generally lean toward the NUCLEO-144 boards as there are more pins, less compromises.

Of those the F4 models perhaps have the longer lineage and code examples.

I quite like the L4 series for general work.

For math work, the CM7 in either the latter F7 or H7 series support a single/double precision FPU

Screens/Displays, that can get very subjective, I personally quite like I2C interfaced OLED displays using the SSD1306/1309. You can paint/draw your own framebuffer, doesn't take overwhelming resources on pins, memory, etc

For radio related projects theB-L072Z-LRWAN1 uses the L072CZ, which has quite a lot of memory resources, and is quite versatile.

[Tesla DeLorean]

The HAL library does afford the ability to migrate between dozens of boards/parts relatively easily.

If a lot of tutorials, step-by-step and hand-holding is involved, it would make sense to pick one board and be comfortable with it, and supporting it. My view is that they are all much more similar than they are different. Being nibble and adaptive might be a better real-world lesson, this stuff is evolving rapidly, and skills building an 8051 based thermostat or weight scale are a bit neolithic.