I contacted Pacific Valve about two months ago to try and buy a REF-7.
I was told they could order one but they were only going to stock the new
NFB-7 and should have some in three or four weeks.
After about four weeks I e-mailed them and asked about stocking status.
I was told their order came in but all were sold. They said it would be another three weeks or so before they had anymore. I put my name on their waiting list.
After another three weeks I e-mailed them, only to get the same answer.
I was told I could give them a credit card # and pre order one.
I then decided to just order from W4S.
Maybe after the first of the year they will be more available.
Like you i am curious as to how they compare to the W4S.