I have been using these powders for some time now: [N133, N135, N140, N540, N150, N550, N160, N165, N560, N170, N570]
Have not tried N555 nor N565 yet.
My experience with Vihtavuori Powders has been very positive. They are clean and consistent, lot-to-lot.
I had one tin of N150 go bad on me, but had no history on storage, etc, so may not reflect a flaw in the product.
I like their powders, and will continue to use them. [ my 257 Weatherby loves 110 Accubonds and N570] Dave.