I think nobody would argue IST is a better airport to transit, but I just do not like the SIN gate security. I always end up being either too early or (almost) too late at the gate.

PS> I think IST & ZRH moved away from gate security to centralized security within the last couple of years. ATH are doing this right now. So it is only SIN, KUL, KWI, CAI T3, BEG, VIE (the old non-Schengen terminal only) that are left with doing security checks at the gate.