Best Hoya ND filter?

Hoya sells three lines of solid neutral density filters, each one using a different technology. Have you worked with all three? Does the more expensive line give meaningfully better results, or are we splitting hairs? Context is long exposures (6 stops and above) of landscapes using modern digital cameras.

1) ND, three-layer HMC coating = reduces flare

2) Pro ND, metallic ACCU-ND coating = maintains color nuetrality and consistency.

3) Solas IRND, anti infrared coating = supresses color casts in shadows.


https://www.bhphotovid​eo.com …s_27%7c77mm&N=4​026728350&

Update:

The PRO ND series has been discontinued. The Solas IRND, Hoya's top-of-the-line neutral density filter, does not come multi-coated like the Pro ND did, but I am told that doesn't matter because filter flare is negated by long exposures.