I pigeonhole (with broad license) Ault/Clark's work into three periods - new course design by Ed Ault in the 60s-70s, renovation in the 80s-early 90s by the firm reorganized as Ault/Clark, and recently new course design - particularly high-end daily fee courses. I haven't seen their work outside the DC area but they've done so much here that I believe it must be representative.
The early courses were munis and mid-range resorts. The designs were pedestrian - large flat greens flanked by oval bunkers, an occasional fairway bunker, unimaginative use of land - but immensely popular. Falls Road and Northwest Park are good examples from this era.
Their renovation work was also forgettable and much of it has been forgotten in the past few years (Chevy Chase Club, Congressional, Bethesda, my old club, Manor have or are in the process of re-renovating A/C's work). Oval bunkers were replaced with cats-eye shapes; mounding was also popular.
The new courses are very much in line with high-end, non-minimalist modern design. Several courses in the area - Worthington Manor, Clustered Spires, Cross Creek, South River - have tried to tap into the mid-upper fee market. They all have their moments and can be good value but for a memorable golf experience, I have a hard time distinguishing them from courses designed by other architects in this area - Art Hills, for example.
I will echo Wayne's comment on Harrisburg CC. Their redesign stands out like a sore thumb, to coin a phrase.