I've seen both impressive (colorful, bright, straight overhead and fast movement) as well as barely noticeable (colorless bands/sheets that "look like faint clouds but somehow odd". With the "odd" mostly meaning that they move different from clouds; not preferentially in wind (or any) direction, and often just around our eye's threshold. It also, sometimes, looks like a band of light pollution low along the northern horizon, when the green main aurora oval is "just" visible.

Few-seconds exposures on a digital camera bring the colors out that you may or may not see by eye if the aurora is weak.

Also, especially mid-latitudes, sometimes an Aurora display has moments of higher brightness with color, and then again "grey curtains".

The most impressive thing about stronger Aurora, to me, is the "fine structure", the fact you may have it well overhead (not just on the northern horizon) and the fast movements. It can look like "beads" running up and down the curtains, or "lances" being thrown from the sky, and line/streak structures are very sharply outlined, not like the soft blur in multi-second pictures. And the curtains can "wave" across the entire sky in a second then.

But I haven't seen enough Aurora to dare predict anything ... I cross my fingers.