Cons:
1. When venting/exhausting, it does a horrible job. I know all about the cfm rate and how it measures to larger fans (the transom unit is 185 cfm while my large vornado is 585 cfm), it still should draw in some fresh air from an open window while everything else is buttoned up, except of course the other window with the transom fan in it. I made sure everything else was sealed up, I even put a towel at the bottom of my front door, before I tried the exhaust test. And we're only talking about an 850sqft building. The inability to exhaust seems to be as issue with other reviews.
2. Safety. There is no way of locking the unit in place, save for attaching your own brackets. Ne'er-do-wells would have difficulty pulling it out, but they could push the unit in, turn it, and pull it back out through the window, or worse yet squeeze through the opening. I accomplished the first feat, the second could be accomplished by someone smaller. It's the weirdest design. I can't explain it, but there's just a thick, foam strip across the bottom that sort of locks the unit into place. You might also be able to secure it by cutting sticks and wedging them into your upper window preventing even the slightest bit of room to wiggle the unit.
3. Those darn foam blocks. In lieu of using the accordion style sides, like so many window ACs, they give you these weird foam blocks to fill the gaps. The blocks were also formed a certain way which didn't match the gap my open window made. Maybe my window is atypical, which I doubt, but there was some serious gaps. And of course they don't compress all that well, either, so when I was trying to get the last one in, another would pop out. It was akin to a Three Stooges bit. I tried it for a few more minutes, then I just measured the openings to make my own blocks, cut them out insulation board, wrapped them in weather seal, and used those. That worked so much better and left zero gaps and light pinholes.
4. Again, it seems woefully underpowered as a whole. I wasn't expecting an industrial turbine, but I was expecting something more powerful than my range exhaust fan when set to exhaust.
5. The controls seem awkward and unintuitive. Plus, on the main unit, they're touch control, too, which is clunky as well. The remote seemingly only works when you are directly in front of it, and is equally as clunky to use. The remote also is powered by one of those button batteries, which I hate. Either make it rechargeable, or power it with AAA batteries.
6. There is no way to direct the incoming air. I knew there wasn't going into this venture, but after trying it out, I really wish there was something, like louvers or something.
Pros:
1. This is the biggie. This one almost negates all of the cons... When drawing air in from the outside, IT DOES AN AWESOME JOB!!! Can't stress this enough. It really sucks in the cool summer air. A huge difference. I did a test where I shut my bedroom door and let the transom unit cool the bedroom. The rest of my place I just had the windows open. When I went to bed there was a 10 degree difference between the thermostat and the thermometer in my room. I just wish I could have directed it towards my bed.
2. Low profile. Unlike other window fans, the unit only takes up a small amount of space, leaving your windows quite unobstructed.
3. It's quiet. Whenever a product is touted as quiet, I always roll my eyes, but this baby is quiet, even on high.
4. It's lightweight. Easy to move from one window to the next, should you feel the need and want to wrestle with those foam blocks.
Summary:
When it was all said and done, I am taking it back. I could live with all of the cons except one... the safety issue. If there were a way to lock it, my review would still be the same, but I'd be keeping the product.