In my opinion, Hettich Quadro slides are every bit as good as Blum, but not so famous, so less $ with soft close. Have your cake and eat it too!

No experience with Liberty. They appear to be side mounted. Hettich & Blum are undermounts. Lose space underneath, or lose width. Undermounts are nice because they are invisible and drawers pop right out if needed.

Blum, Grass-for undermounts - maybe KV or accuride but both make better side mounts. IMO not the best place to save $$
I'd get side mount accurides first and you gain drawer height.
As to soft close- I only have it on 4 drawers, wouldn't mind if it were only 1. .
I disagree about hettich- put some down perssure on a drawer as you push it in, noticeable difference. I'd give up soft close before durability.

Thanks for the replies. My only drawer stack is 18in wide so Im thinking width is more important than depth. Have to check where the slides are mounted.