AZ in Colorado Springs
My router table is a Rockler high pressure laminate table, and I made a simple base for it. For a couple of years, I had an old skil plunge router mounted in it, and I added a shelf under the router and used used a bottle jack (hydraulic jack) as a lift mechanism. I could raise the router in fine increments, but going down was trouble. But, it worked.
Then I got a freud FT3000VCE (Woodcraft had a great after-Christmas sale a couple of years back) and mounted that. It is a plunge router and is adjustable through the base. It also has a shaft lock, and I can easily change bits above the table.
The freud router came with a knob that was not very convenient to use. The adjustment mechanism uses a 3/8" allen wrench, and the knob was a length of the appropriate aluminum stock with a small knob handle at the end. I found a socket in my tool box with a 3/8" allen wrench end. I use a ratchet and extension with that socket and I can make very, very fine adjustments in both directions. And, the ratchet handle, more so than the knob, makes it easier to make the finer adjustments -- 1/4 turn, 1/8 turn, 1/16 turn, etc. And when it's time to crank it up and remove the bit, I don't risk a repetitive motion injury to my wrist turning that small knob.
To get to your question, I've never used a separate screw-type lift mechanism (just my bottle jack). But the integral system in the freud router is great.