Speaking from experience here... Selling 1800+ LLLL.coms was a painful experience. First off, you know you can't be selling them 1 by 1 unless you intend on doing this as a full-time job for the next year!
Secondly, keeping track of all the LLLL.coms that are sold requires a ton of dedication, focus, and effort. Replying to 20+ pms and email inquiries a day takes it's toll as well (on some days I had upwards of 50!).
If you're going to be bulk selling/buying, make sure to assign yourself an hourly wage and see how much you're really making. I was putting in 3+ hours a day (note: I have a full time job as well) replying to pms, emails, and updating my list of available LLLL.coms -- and I couldn't keep up, my lists weren't up-to-date, and sometimes pms went unanswered. This went on for upwards of a month, before I decided to just seek out bulk buyers and sell at a discounted rate.
Now that I've moved into premium LLLL.coms (quad premiums, triple letter, VCVC, CVCV), it's an entirely different story. I carry 95% less inventory than before, yet am making a somewhat comparable income -- with alot less headaches!
If you're a full time domainer, I'd go with the lower quality names, just because as mentioned earlier -- you have more chances of finding endusers. If, on the other hand, you do this part time like me, I say the less names the better
Besides, you can use all that time you saved to seek out bargains...