Check this link out, there are pictures of several different converters. Ones that come with the kit pens, and Schmidt converters which are made a little better. Better rubber seal and some extra metal bindings. http://content.penturners.org/articles/2007/fillingfountainpens.pdf
I for one really like the metal bodied "areometric" style converters that Lou sells. They make our kits pens appear much higher in quaility than the ones that come with the kits.
I have been using one of Lou's vacuum converters on an Emperor pen I've been writing with lately. It is the one shown in Lee's photo above. This is a really nice converter! I am very please with how it is functioning.
I decided to break out the Emperor for a little test writing. I made the dang thing for an article I wrote for More Woodturning over a year ago, and it's so expensive I can't sell it to anybody. Lou was asking what kind of pen I write with, so this is the one I grabbed, and he sent me some nibs and converters to try out. I'm still in the middle of my nib test, but so far things are looking good for Lou's nibs! And I really like these converters. Guess I'll have to buy some more of them!