I've been learning Vi/Vim for some month and, at the moment, I'm editing many files at once splitting the window, jumping from one buffer to the others. I find it very useful.
One thing I don't like is when I have to execute commands in the shell from within vim. I use, for example
:!make. This is easy to do. But when I have to run some executable I'd like to use command completion regardless of the case of the letters of the name. For instance, suppose I have to run an MPI program with
:!mpirun -np 8 Convection1D; actually I'm not so fast in typing the parts
-np, but I could save time by using command completion for the name of the executable. The obstacle is the capital letter (or letters); it'b be very good if I was allowed to type
:!mpir<tab> -np 8 con<tab><enter> (especially considering that I can press tab repeatedly to view successive completions).