I've used the same Gaines wheel on my basses for 30+years. Every luthier I've asked about the effect on the bottom block says the same thing: "be sensible". to that end, I don't run the bass off 8" curbs. I lift it down and back up. I don't let the wheel get so soft I can't move quickly and maneuver through crowds, but I keep if soft enough to absorb bumps.
IMHO, the wheel in the top post is junk. It's supported on only one side, which is simply bad design. I've seen a few of this style after a few month's use, and the wheel is usually at about a 30 degree slant off vertical to the unsupported side. The Bass Buggie is great if you go from your house to your car to the gig, but I wouldn't want to hump that much added weight up and down too many flights of subway stairs. I find the two wheel device hard to steer as well-you have to follow the bass like it's a hand truck rather than just slanting to turn.
Also, the Gaines wheel has a replaceable tire (I'm on my third) and the shaft can be changed to rib-forward or top-forward (my choice-see "Whims of Chambers") and to whatever size endpin you have.