Earlier quoted context omitted.
If you say why Gedit was faster perhaps us vim fanatics can help you understand us.
Let's say I need to change a word. With Gedit, I double-click the word and retype it the right way. With Vim, I press j until I'm on the line where the word is, then I press w until I'm at the beginning of the word, then I press cw to change the word, retype it the right way, and press escape to go back to command mode. Triple-clicking in Gedit highlights a line. Triple-clicking and dragging highlights a contiguous g…
OK, this is something Vim people need to work on. Using j/k to move more than one or two lines is the wrong way to do things.
I know, I know, we extoll the virtues of hjkl constantly, but really they're barely more effective than the arrow keys.
There are better ways to move around in Vim, such as [f]orward, '[t]il and searching. In your case (changing word XYZ to something else) I would search for the word with /XY… and press return to get there, then edit as you described.
"Triple-clicking in Gedit highlights a line. Triple-clicking and dragging highlights a contiguous group of lines. In Vim, I'd need to move to the line I want to begin my selection on ([number]G or jjj), then press V, then press jjj until everything is selected."
See my previous comment about movement. You'd move to the line you want by using a search (or '{', which moves to empty lines), start your selection with V, and move to the end with another search (or some kind of movement command that gets you where you want to go quickly).
We Vim users need to stop touting our Nethack-honed hjkl skills and start talking about Vim's better movement commands.
"And I don't have to deal with the fact that the default way of deleting things overwrites the default clipboard either."
Yeah, this is dumb. YankRing helps a lot by letting you 'Ctrl+P' to the right text, but I really think Vim should have a "clipboard register" that only gets overwritten when you mean it (and have other registers for the last yanked elements).
"when I paste code in to a Vim document, the indentation gets all screwed up."
If you're using a graphical Vim like gvim or MacVim this simply shouldn't happen. It's a bug and you could report it.
If you're using the command line Vim you might need to do a bit more work to launch Vim and tell it to talk to X. It's a few extra minutes up front, but such is the price of using a terminal-based editor in a graphical environment.