It looks fine to me and is as readable as the text on heroku itself
Not exactly a paragon a legibility.
If you're going to pick a dark background, choose a color for the text that will actually contrast and be legible for the widest audience possible, not a shadowed, slightly lighter version of the background.
In essence, this "alternative" does absolutely nothing to improve upon Heroku's version. It's also worse.
If you build something that people can't use, you've wasted your time. That search box on the left is useless unless someone a) understands how Heroku works and b) knows what they're looking for in the first place. Reviews? Ratings? I guess they work for Hotscripts.
Heroku add-ons are for people who already understand the architecture of their app, not necessarily some guy looking to add something on for the sake of it, hence the obvious pricing. You have to know the audience.