Before anything else I say, keep in mind that Vi/Vim is a text editor; meaning, it can't "give" you anything as a Perl development tool, or as any other language's development tool. Especially, it can't "give" you anything special compared to other editors/IDEs: Syntax highlighting, auto completion, tag recognition, indenting and "prettifying", combination with other tools, macro definitions, all are available from other editors as well. (Whether a given tool's choice can "give" you anything is another debate, which I'll ignore for the moment).
This been said, Perl development isn't something that requires an IDE, but a text editor. The reasoning is twofold; one, out of the IDE trio components - Compiler/Editor/Debugger, only the editor component doesn't arrive built-in perl, and two, Perl doesn't unload its interface at you, in the sense that you don't need to call String.Regexp.Read.Compile(Match.Test.Show()).ToString() where a simple =~ will do.
This makes your choice of the editor tool, somewhat more significant, but the actual choice is less critical.
Vi's modal interface allows you to text-edit in a way that is akin to playing a fast-action game. Without removing your hands from the keyboard, you can edit files using complex commands in a relatively fast way. To get on top of the interface, you'll need to learn the Vi key-modes, which is slightly like learning to touch type. As with touch-type, once you get over the learning curve, your editing speed will become much faster and your actions will be much more precise than before
However, other than that change, its importance be what it may, Vi/Vim includes no magic tools, and for that sense, no editor really does. If you like working with TextMate, carry on with it. Those who know Vi usually swear by it, as no other editor gives them the editing speed that Vi does. Those who don't, don't really "get" it, or don't think the one main advantage is actually of any worth, or feel "their" editor's special attack is better than Vi's.
And as always, Your Mileage May Vary.
