To answer your request accentpal,
Truthfully, there is a great market for both pronouceable LLL.com's and for premium letter quality. This said, for my money, I'd far rather have a premium letter combo than one that was simply pronouceable (but not an actual word) and was made up of lower quality letters. The reasoning for this has a lot to do with end-user sale tendencies. I get and observe far more end-user interest in more premium letter quality domains than in domains that are simply pronouceable (but not of quality letter composition).
Perhaps the easiest answer is for us to attempt to put ourselves in the mind of the common end-user market buyer. There are many buyers who are looking for a short and pronounceable name to buy and then market. They have many options at various price levels, and there's often not just one domain that can meet their needs.
On the other hand, there are many companies, organizations, business products, processes and standards developed everyday, and often with an acronym attached. Very often these acronym's are composed of premium letters. The owner of any premium lettered LLL.com probably has multiple end-user possibilities already, but probably also has more and more options growing daily. If he or she doesn't need to sell today, they can just wait and their combo will probably be even more desireable as time goes buy (as more end-uses are become newly possible).
It's somewhat unsatisfactory to say that this could be a both/and situation, as there is truly a strong market for both types of these domains. --> For my money, a premium letter combo wins everyday between these two...but then again, owning any LLL.com has been a great investment over the years and there's a lot of reason to believe (imho) we've only just begun to see the growth in this segment.
I hope this is helpful,
zesty