Eclipse + GNU ARM + STM32 - HAL or SPL
The SPL, as I see, has nothing to do with what IDE you are using. You can simply include the relevant modules (e.g. stmf4xx_dma.c and stmf4xx_dma.h) in your project and use the functions exposed (and described very well) in the .c and .h files. In fact I've been learning on the stmf411 nucleo with gcc, openocd and SPL using just the windows command prompt; no IDE. Packages in eclipse probably would force you to use the HAL (since inside the downloaded 'Packages' folder for eclipse, I only see HAL modules).

The HAL itself IMO seems far much layered than necessary. Whereas accessing the registers directly gets tiresome and is hardly readable. The SPL seems just right. clive1, the guru on the st.com forum, also prefers the SPL over HAL. Here's my question on that forum... might be helpful.

Need help with USART on Nucleo stmf411