Is Park Tool Polylube "waterproof"? I just ordered Park Tool PPL-2 Polylube 1000 Grease Tub (1 Lb) from my LBS.  I was surprised when they didn't call it waterproof and tried to steer me to a Phil Wood product as the waterproof one, because I thought I'd seen Polylube described here as waterproof, i.e., suitable for unsealed bearings.  Nothing against Phil Wood, I just thought people said PolyLube was waterproof too.  Is it?

The Park Tool site says "repels moisture".  I assume that's the same as "waterproof" and the LBS person was just misinformed?
Different greases hold up varyingly well in different applications, depending on levels of dust, water, temperature, etc. 

Park Tool Polylube PPL-1/2 are your basic bicycle greases -- they hold up well under most people's riding conditions (including repelling water enough; others like Phil Wood or Park Tool HPG-1 might be more water repelling). Depending on the conditions, you may end up repacking a bit more often than others, but its not really all that big of a deal, so long as the grease is doing its job (which for most people, it will just fine; if you're riding in -50 C, you might want to pick something else). 

At the end of the day, note that many people are using just regular old multipurpose grease from the auto shop (that red stuff Valvoline sells for less than 5 bucks a pound) or marine grease and are doing alright (it's significantly more viscous than bicycle greases so not ideal; however, note that even a tube of Park Tool PPL-1 will last you quite a while, so the cost savings aren't immense for the home mechanic ). So, don't lose sleep over this.