Best speaker brands for transient response

Even if you get to audition candidates, if you don’t hear them in your own room, you still have that uncertainty.  It would be hard to find dealers who have the speakers you are interested in and are will to loan them out.  I see how the Mofi speakers are less of a risk at the much lower price and a chance to hear them at the dealer.  I hope that works out.  It would be an even better audition if you get to hear the speakers with your amp; perhaps the dealer will allow this.  The amp-speaker interaction is particularly important to the sound.

Even if you get to audition candidates, if you don’t hear them in your own room, you still have that uncertainty.

Agree 100% and don’t view in-showroom auditions as the final step. I haven’t bought the amp that will drive them yet -- I wanted to narrow down to a few models and then research amp options that appear will be the best match to my speaker candidates (with a bias toward wanting to buy a Parasound Hint 6 if it appears it will be a good match).

A good example are the ATC SCM40s, which based on feedback on various forums and reviews will require a bigger investment in amps compared to say the Spendor 7.2. The Spendor also, based on better sensitivity, will probably play better at low volumes while the ATC appears to need to get a little loud to open up (true of my KLH 3s as well). I don’t play music particularly loud so this is something I need to consider, as well as the Spendor probably being more flexible with amp choice.

I agree the Mofis may be a safer choice that enables some additional learning/experience to make a more informed choice at higher price points down the road.

Not the only choice, but ATC speakers allow you to 'see' inside the music with excellent detail, fast response to instrument/vocal attack in a very balanced way (when driven properly).  Most other transducers seem slow and muddled.

One of the challenges with ATC is properly pairing their sealed cabinets and rather large magnets with stable current to control the drivers.  Sealed cabinet designs usually present a more difficult load.

Enjoy your quest.

One of the challenges with ATC is properly pairing their sealed cabinets and rather large magnets with stable current to control the drivers.  

I'm going to assume this is why they offer so many of their models in active designs.

I've owned/own four different pairs of ATC speakers.  Two active, two passive:  ATC 40A, 50A.  ATC 7, 20.  Even the small ATC 7 at 7 liters needs my Sugden A21SE class A at 33 wpc to properly push them around.  The ATC 20 needs the 125 wpc Luxman 509X to control massive magnets.  

Just saying that some may under power (translation, not enough stable current) sealed cabinet speakers producing anemic non-involving results.  Some will blame the transducer, that is not where the problem lay.

Active is where I live for reference, but the passives are also quite good.