With heavy eyepieces (only), my scope dives when pointed below about 45° (good reason to not look that low, I suppose, and everything is better higher up anyway).
A small mini bungee provides just the right amount of lift, and the lift increases as the scope points lower. That's also a good thing.
But a variable, or "virtual" counterweight has a couple problems:
--it raises the scope when changing eyepieces
--it can only truly balance one weight of eyepiece (and mine range from 6 ounces to 36 ounces, which is a problem)
The issue of imbalance can even affect the "perfectly-balanced" scope when an eyepiece is changed.
So the desirable accompaniment to the "virtual" counterweight is a brake of some sort that holds the scope in place while the eyepiece is being changed.
But, I like the virtual counterweight because as the scope moves lower, it effectively increases the weight of the counterweight.
Otherwise, I'd have to be diligent to change the weight on the scope depending on the altitude of the target.