This tea can hardly be compared to other sencha using the common vocabulary. There are flavor notes here that are so delicately floral/fruity/malty and etherial I am still struggling to find a vocabulary. But taste being on the bud of the beholder, my main reason for commenting is to offer what I hope will be useful information for anyone hoping to get the most from this outstanding tea.
Get the best water you can find and one with a neutral flavor. Distilled is too flat and harsh; some spring waters are too mineral tasting. Without testing every water on the planet, I have found Aquafina to provide excellent results in making all kinds of sencha.
It is especially important with such a fine tea as hibiki-an's Sencha Pinnacle to get the water right. Moreover, you should boil your water in glass. I have taken to microwaving my water in the glass beaker of a coffee press; this way there is zero additional flavor imparted to the water in the boiling process. If you have a glass pot that you can use on your stove, problem solved.
Finally, 175 degrees F. is too hot for this tea. Don't go above 170 and watch your timing. One minute should be sufficient. You will achieve very different results with this (and other) tea if you steep a) too hot, b) too long and c) with bad water.
Sencha Pinnacle costs enough to sweat these details, and if you get it right you will be amazed at the exquisite flavor of one of the finest green teas you can find.