I have the First Luvs. They are GREAT!
For about 15 hours worth of ski time.
They turn like a dream and are "forgiving", which means "noodle-like".
I found them amazing to learn on, then found that I improved on them so quickly, I grew right out of them.
And I found them a little skeery at speed. Don't get me wrong, I loved them, but not for long.
I then moved straight to the Tru Luvs (year important as the 11s are rockered, not much at this level, but still...)
I went directly from shorty First Luvs to the Tru Luv 149 (I'm only 5'3" after Pilates class), so these are
actually a bit longer than chin-high on me.
As for "intermediate", eh. I had no trouble on them, at all, and I was still a beginner.
But I think part of my success on them is that my boots are good and the rocker makes them ski shorter
than they are. I found that the longer length reaaalllllllyyyy kept me stable on variable snow.
I found that I had trouble maintaining fore/aft on the short skis when I had to deal with transitioning from
hardpack to soft snow and back. My "recovery" moves are not as graceful as I'd like. That didn't happen on the
stiffer and longer ski.
I would think that at 5'8", the 149s will be too short.
My personal opinion is that I'd go with the longer ski, even as a rank beginner.
They help you improve, fast. And boots, boots, boots, boots, boots, lessons, lessons, lessons.
I'm already thinking I'll be on something "advanced/expert? by the end of next season....
They just feel really stable.