Leicachamp, while i have not heard the Leben gear myself, i have been steadily making my way up through the Shindo line without regret. I've gone many different directions before I found Shindo...Ayre, ARC, Counterpoint, Bel Canto, Aesthetix, ASL etc....and never kept any of them for more than 3-6 months before trying something completely different each time.
With Shindo, i've left that madness behind and now just enjoy my listening time...to be honest the only time i'm looking to upgrade is when a used Shindo upgrade finds it's way to the market but even then there is the law of diminishing returns and to be honest, i've gotta be pretty close.
My current setup is Shindo Masseto/Cortese and it is simply sublime. It is more expensive than the Leben gear but the dealer network is highly supportive and some allow very generous trade up offers. I've heard the Leben gear is excellent as well and may suit your listening style perfectly. Many Shindo dealers also sell Leben so there is a similar pedigree. At the end of the day it's what sounds best to you and allows you to stop the hunt and enjoy the music. Cost is largely irrelevant as far as quality is concerned in this hobby...Many folks just like the chase or are consumed by it and will spend countless dollars in pursuit of perfection that is impossible to find...Me...Well i just like to kick back and listen to the music.