The full report on the rassler will be published on blistergearreview.com
in a couple of days. For now though, I'll lay down some of the differences between the Rassler, Water Tennie, and Guide Tennie (I use them as everyday shoes and approach shoes).
Basically, I personally wouldn't use the Guide Tennie for anything water related. The shoe isn't meant to get wet. That kind of material is going to get really heavy when wet and it won't drain. It also won't dry out quickly after boating. Shoes that stay wet rot, and that is the fastest way to wreck a perfectly good pair of shoes. If you do decide to use them, I would investigate punching some small holes in the sides so they at least drain a bit of water.
If you don't want to spring for a water-specific shoe at that $100-$120 price point, I would recommend using something cheaper and less wreck-able than the Guide Tennie. Look into amphibious trail runners, perhaps.
As I mention in the review of the Water Tennie
, it is a really worthy creeking bootie. The traction is great, it stays on my foot, and the high top keeps dirt out. The mesh material drains well. It really is more of a bootie than a shoe, however, and that becomes especially clear compared to the Rassler.
The Rassler has a much stiffer, thicker, more supportive sole and heel. It moves more into the realm of an actual "shoe" as opposed to a sturdy bootie. Traction is comparable to the Water Tennie (same rubber). One thing I really love about the Rassler is how it dries out so quickly. There aren't any removable insoles in the shoe to trap water, so you cut down a lot on smell + a shoe that dries fast lasts longer.
The other difference is fit. The Rassler has a lot more volume in the heel (space behind your foot). So if you have a large heel, this will be more comfortable. The Water Tennie will be more comfortable if you have a small heel. Rasslers seem to run a bit large- I ordered a half size smaller than usual.
Durability is a concern with both of these shoes. I've had two pairs of water tennies that lasted a long time and one pair that imploded quickly. I haven't had the Rassler's for long enough to know, but the Brewer didn't have a reputation for durability.
Personally, I would probably slightly favor the Rasslers for my needs because they are more supportive and dries wicked fast.
If you are mostly planning on day use, or need a shoe that fits in the boat easy, the 5.10 is also great. Both worthy shoes. 5.10 is a "sturdy bootie" whereas the Rassler is more of an actual shoe.
Full report coming soon. Hope this helps.