Jarvman,
I have a copy of this lense. I bought it for several reasons. First it's rather small for a 90mm since it collapses and it is fairly light, so it makes a pretty good travel lense. It makes a nice portrait lense. It focuses to .76 meter and as a 90mm you can fill the frame with anything that's the size of a larger flower, such as a day lilly. Even though the largest aperture is fairly small at f4, it will blur out a background quite nicely for a portrait or close up. It uses a 39mm filter, so it is the same size as my other three lenses and when I bought it it was fairly reasonably priced for a Leica lense at around $1200 (three years ago). I bought it without the macro adapter, but I would like to try it with one someday. Overall, it does a number of functions very well. If you have any specific questions, I have the lense and the manual, so I'd be glad to look up an answer if I do not know it.
Tom