I have a 36. I've heard of people having some problems with them, but mine has gone bang every time I've pulled the trigger. I'm not really a Glock person, but I got this one for CC with the hot humid Florida summers in mind.
I don't own either so my opinion may not mean much..but when I was lookin for CCW I looked at the G30 and G36..the size difference was not noticeable enough to give up the extra rounds..in my mind if I want a smaller 45 I would have grabbed the XDS
selling my 36 but not for the reasons that people give that they have problems mine went bang every time...glocks are great guns ..just not my cup of tea..im a 1911 guy and have been most of my 61 years of life..some things are hard to let go LOL
I owned a 36. it was reliable and accurate, but it was not much smaller than a Model 19 or 23 both of which are easier to shoot quickly and hold more ammo. If I was to purchase another compact Glock in 45, I would go for the Glock 30.