Downunder, when I say "darker" I'm talking about a slight roll-off in the treble, which translates into the slight lack of air (especially compared to the IO) in the treble range that Jonathan is referring to and a tonal balance more tilited to the midrange than the treble. I would call the bass and midrange very natural, not warm, but with the lack of treble emphasis some might call it that overall. This is the sound I tend to prefer, so I do not see it as a drawback for me. I should mention that one other thing the Lamm seems to excel at is reproducing a very three-dimensional soundstage; layering of instruments in the soundstage is excellent (which is its biggest advantage over my JP200's phono stage and why I use it along with the JP200's line stage). Dynamics are good, but probably not as startling as the IO; bass on both of them is excellent, you would not know either of these was a tubed unit.
On the reliability question of the IO, a friend of mine (with my urging, as I heard it for the first time with him and thought it was extraordinary) bought one of the early IOs back when no one had really heard of them, and has been happily listening to it with no problems for over 8 years. I have no reason to doubt Jonathan's warnings from his experience; however, having the local tech nearby should ease any reliability concerns you might have.
On the gain question, I lived for years with a Koetsu Rosewood Signature Platinum (VERY low output cartridge) and the Lamm with no real problems, but the lack of gain was enough of a bother, particularly on large scale orchestral works that might be cut at lower gain levels, that ultimately I did replace the Koetsu with a higher-output EMT cartridge. Jonathan's right, a low output cartridge will work with the Lamm, but there are times when you wish you had just a little more gain.
