I too have a cheapy and a $400 one and have to say the $400 is superior in every way...and will last forever...while I would not trust my $1500 lenses to be connected to a $30 adapter. If you do just that, then good luck and I hope you don't one day regret it. Also, my cheapy adapter does not have a tight fit on the lenses, there is play...hence my distrust!
I too think the birger is really cool and hopefully they'll come out with a comparable nikon compatible model someday, because I was originally going with canon, but then realized you need a $700 adapter just to be able to use the iris, while nikon has its little lever. So if I get some other brand or new model of camera, I could not use the canon glass' iris unless there were electronics...and with nikon it is then much easier to get a usable adapter out.
I too think the birger is really cool and hopefully they'll come out with a comparable nikon compatible model someday, because I was originally going with canon, but then realized you need a $700 adapter just to be able to use the iris, while nikon has its little lever. So if I get some other brand or new model of camera, I could not use the canon glass' iris unless there were electronics...and with nikon it is then much easier to get a usable adapter out.