The phrase "about the most impressive" is correct and usable in written English.
It can be used when discussing something that is among the highest level of impressiveness in a particular context.
Example: "The presentation was about the most impressive technological advancements of the year."
Alternatives: "one of the most remarkable" or "among the most outstanding".
With their latest acquisitions they have just about the most impressive array of Eastern weapons & accoutrements in the world but only a fraction of it can ever been seen at one time.
9 40am Keynote – Choosing the investments – and products – of tomorrow: a venture investment view 10 15am Innovation, incorporated: panel discussion about the most impressive recent green innovations, and what made them possible 11 05am Break 11 35am Workshops: how can we spur the next generation of green innovation?
Daqri has some more news coming up, so I don't think I'm supposed to talk about the most impressive demo that I saw, at least not yet — but, well, it was impressive.
Indeed, when we first wrote about Laura Mvula – arguably the most impressive new solo female artist of the year – we pre-empted the article with a list of the other contenders, which took up most of the first paragraph.
PayPal is often talked about as one of the most impressive companies in tech, both out of its impact financially and the bevy of talented operators who got their start there.
During an FGD, a group of 4th grade children explained how they felt about the HWWS intervention: The most impressive and exciting thing in the past month was the HW-with-soap exercise, especially when our hands were clean (sạch), soft (mềm) and perfumed (thơm) ….
The merlots have been the most talked-about wines, but to my taste, the most impressive wines from the North Fork have been cabernet francs.
The most impressive thing about "The Tenth Parallel" is that Eliza Griswold lived to write it.
The most impressive statistic about the Tigers may be that they have allowed 13.1 points a game.
