I've found that anything that pre-searches potential site hits will slow down your browser. I've seen it with Antivirus trying to 'inform' me of potential bad sites, as this one indicates is it's function. However, if safety is your main concern, as the quoted portion by mouser states, 'the cautious user', perhaps the wait is worth it.
I've found in personal experience, the only sites I should be especially wary of, are usually associated with
No CD/DVD workarounds and the such.