Paul there are a number of large format two ways that perform superbly from Augsberger, Rey Audio, TAD and Quested.

There are three and four ways from Westlake and TAD.  All of these are every bit as viable as ATC's in my opinion. One advantage of many of these is that they share their crossover point with the original Quad, 800hz and are phase linear in most cases beyond that. The ATC sadly has a fourth order right in thr middle of the presence zone, and very close to upper frequency break up modes.