Mocolo's glass screen protector isn't as good if you ask me. I bought from a seller that claimed it was Mocolo and the oleophobic coating isn't as great as glass screen protector from other sellers at less than $10. Unless it isn't actually Mocolo?
Anyway, I would say it's worth the extra to go glass. They are normally a lot clearer than normal screen protector with little to none colour distortion (rainbow effect when viewing at angle). Those with good oleophobic coating will feel smoother to the touch too, and will accumulate a lot less fingerprints then even those matte anti fingerprint screen protector. They are a lot easier to clean too.
I haven't encountered any downsides. Touch response are still as good as when it was naked. If you ask me once I went to using glass screen protectors, I've been getting it for all the phones that I use. It's hard to go back. They are more durable too and less susceptible to scratches, so meaning need to change less often. End up save more over time if you ask me.