I use Sidi Adventure Rains, but I also just picked up a pair of Gaerne G Adventures recently because they were blems and I got them dirt cheap. The Sidi Adventures seem to be a good balance between protection and comfort and they have been totally waterproof. But they squeak, if untreated, and look like motorcycle boots. I commute on the bike regularly and swap to normal boots once I get into work. It would be nice to have a pair of boots I could leave on all day. The G Adventures I just got might be able to do this and look a bit more subtle under my pants, but they are far less protective than the Sidis.
Previously, I wore hiking boots. The main reason I switched really wasn't for safety. It was because I wanted waterproof boots - not just from rain, but also from water getting in over the top in creek crossings. I had been using some waterproof Redwing hiking boots, but I basically ruined them from stagnant water getting in over the top. And because they were waterproof, the water couldn't get out or dry quickly. I'd probably still wear hiking boots, but the ones that are tall enough and protective enough are usually too bulky to be able to shift properly, especially protective toe boots.
I still keep thinking about selling the Adventure Rains and getting a pair of Gaerne Balance Oiled boots. Much like the Sidi Adventures, they seem to be a good compromise between comfort and protection (more toward comfort), but look like normal boots under your pants.