I have a W/400 I havn't used yet. I did research this question before I bought it. The W/400 lays clear a little better with a little more ease, especially by those that are accustomed to Conventional paint guns but uses slightly more material. It is 'Compliant', while the LPH-400 is LVLP (HVLP w/ low air consumption).
I have used both and like the lvlp 1.4 with optional base cap.
It is excellent on hard metallics and breaks the HS clears up real nice but I have not used it to spray an allover clear job yet and because I'm a fast sprayer I'm afraid it might be a little slow for me on a big job with clear but my Sata RP does good with the clear and the new RP3000 is even far better
so may get a 3000 just for big clear jobs.
My lph400 has avery soft feel to it and sprays really nicely. It is however a very slow gun if you know what I mean. I don't care for it for an overall gun. I do however love it for clearing bumpers or a nose of a car etc....
That is my problem, I was taught by an oldtimer who taught me to hold the gun about 4-5 inches -MBC with a 30 cap (lacquer) from the surface and run like heck, I have tried to slow down over the years but everytime I do I screw up.
So guess you can't teach an old dog new tricks.
I guess maybe you could get closer (2-3 in.), if you wana go fast you gotta be sure! If you very your speed or distance much that close, things get bad quick! But, I had an old-timer finally convince me to get closer years ago, back when I knew everything! Spraying Spiez 8030 clear w/ a coat-n-a-half. That was "blowin and goin" incarnate. WOW! To think about it, that was several years ago! :embarrass
I was accustomed to shooting fast years ago with enamel but nowadays I get better results dialing the gun in so I can make slow controlled passes like a robot, at one time I liked fast solvents and hardeners and thick coats now it's slow solvents and thin coats that produce the best results for me. One of the fastest guns I had was a Matson Atomizer and it did break up the paint excellent while also putting out a lot of material with a pressurized cup.
I seem to recall a gun I toyed with for a spell. Thanks to a paint rep. I think it was called a Geo. Boy, that thing atomized right out of the tip, like nobodies business, but you had to pay the price of using a little more air pressure.
As for the robot theory, that totally applies no-matter what technique you use. Nice even robot like passes breed success, fast or slow.