If you've only every worked with one, then things will feel strange when you encounter the other.
My first assembly experience was with 8085 and Z80 processors, which are little-endian (i.e. they put the LSB of a two-byte value at the lower location in memory). It always felt a ltitle backwards to me. When I encountered the 9900, which is technically big-endian (it is actually a true 16-bit processor), everything felt a lot cleaner.
Wade.