Yes, I have heard of the newer Wilson antennas (since Barjan bought them out) having a water migration problem. JJD was the first I heard of it, and now that Pro151 mentions it he is the second. I ran a Wilson 1000 on the roof of my GMC T15 for over 10 years and never had a problem with water migration. I also know several people that are running antennas from the aforementioned manufacturers and none of them have had a water migration problem. As far as being more waterproof, I would imagine it has to do with a closer tolerance between the I.D. of the hole and the O.D. of the (supplied) whip. As I said previously, I'm just wondering if the problem will be more common with this antenna since you supply your own whip. If a person uses a whip that is smaller diameter than the whip that was used to determine the hole size in the antenna then the tolerance becomes larger - which leads to a greater chance of water migration. As was mentioned before, you may be able to eliminate the possibilty by putting a glob of silicone of other sealant on it.
In Wilsons case...I think it has more to do with "Since Barjan took over"...I had a Wilson 5000 that I bought back in the 90's that I never had a problem with, until someone decided they needed it more than me, and swiped it off the back of the car I had it on...
But I bought several back between 2001 and 2004 that the average life span seemed to be only 6 months before they developed a problem...(Loss of ground or shorting out)
First thing you would notice was loss of signal, then if you took the thing off the vehicle and shook it you could hear something inside the coil rattling around...
One of my 5000's I broke apart to see the insides, and it was full of rusty water (wet, not like gallons of the stuff) and what broke loose was at the bottom of the coil where the coax connected...
Think I had 3 5000's all do the same thing....
On one of the Forums, someone had posted a "cut-away" picture of theirs that showed exactly what I'm talking about. Thing looked like it was 20 years old inside, instead of just a few months old....