I see. vim seems to always leave the cursor on the upper-left character of any pasted text, whether it's a paste-above or paste-below paste. This does not coincide with what you want.

However, it does have a feature that no other text editor I know of does. Repeat. So if I do ``I//<ESC>'' (which inserts ``//'' at the beginning of the current line) and then press ``.'', then it does that insert again. A series of ``j.''s (where ``j'' is line down) accomplishes that fairly quickly.

In addition, ``macros'' within vi are quick and easy. You could ``:map q I//<ctrl-v><esc>j'' and that would make ``q'' insert ``//'' at the beginning of the line and then go down one line, at which point you could just press ``q'' again. (Note that this Ctrl-V is to escape the escape so that it doesn't break out of the command you're entering.)

You could also do a ``:.,.+20s#^#//'' and that would ``replace'' the beginning of the line (a zero-character construct) with ``//'' from the current line to the line 20 lines further down.

Of course, none of these are exactly the same as what you're used to. All I can say is that vim (or, at least, some version of vi) is available on pretty much every OS you'll ever touch, so getting proficient with vi means that you'll never have to get proficient with another editor again. That's reasonably true of emacs, as well, but I'm not too good with it.