Depends what you want to do. There are two types, really: Under the bottom yoke type and bottom of fork type. Assuming you want the latter for most maintenance jobs, Pitbull is the best I've used. Some of the pin types interfere with the wheel spindle, makinfg front wheel removal a bit of a struggle.

http://www.pit-bull.com/Forklift%20and%20Converter.htm

Rob..I had one of those pin jobbers and your right about them locating badly. lus my fork bottoms have ben powder coated and it took bits of chuffing paint off.

I now have the cheap & cheerful 'prong' type from busters..still not perfect but much better than the last effort !!

Nat