I got my first Harris in the late 1980's and still like them. I own maybe four of the 9-13" Swivel models now and they're my favorite. My longest shot was with one (bull elk, 451 yards) but my first elk was with a taller model, seated.
But they're either really long and bulky or they're limited to use in fairly open terrain (or a bit of both). I'm learning to use trek poles for a front rest with an arrow shaft attached to one pole, to make a third leg, for stability, and a pair of shortened arrow shafts to make a rear set of cross-sticks.
Those are definitely much slower to deploy than a Harris bipod - if I have a clear position to go prone from I can often get a shot off with the Harris in under 10 seconds but it can easily take 30 seconds or more to get the trek poles crossed, get the third leg out front, then get the rear crossed sticks lined up. Using a pack for a rear rest would likely be faster, but only if you're planning to always have a pack with you in the first place.
In short I'll always have a use for Harris bipods but they certainly aren't the only option or even the best option.