One thing that is constant is the quality of material from Kevin Crawford. The best part of this system is the books are tools and not "cannon that must be followed". I have everything for Stars without Number it is my favorite Sci-Fi rpg.
Now the good things about Engines of Babylon:
You can build about anything from a small motorcycle to slower than light space craft.
More Maltech, I love using this to confuse and tempt players.
The sample Vehicles are well thought out and really cool.
Like everything else Kevin has produced it is well worth the money. I have paid more for stuff I have liked less, sometimes a lot less.
I can find no bad thgings about this product.