Hi Chris,
Yes, and I think the major reasons for injected was 1) it prioritizes injected channels for very accurate timing of samples and 2) there is one data buffer per injected channel, which means you can sample all four and then move data out at the end, instead of either triggering an IRQ on each channel completion or using a DMA (the DMAs seem to have problems running too many peripherals at once...)
The only major disadvantage I see is that you can only sample 4 at once.
Thanks,
-Stephen Dwyer