Removeable Glass Bed vs. Removeable Springsteel Beds
In favor of glass:


Smoother surface gives you a nicer bottom layer (though Kapton-layered steel is no slouch)
More even, regular surface makes bed easier to level
Easy to prep and clean
More scratch-resistant makes getting under a part with a metal scraper a little less harrowing
Corrosion-resistant (glass doesn't rust; silicon dioxide is in fact already about as oxidized as it can possibly be)


In favor of steel:


Flexes for easier release
Safer (steel plates don't shatter, at least not at temperatures you're likely to use them)
Conducts heat better for faster and more even heating
Slightly less expensive on average