Product review (5 stars): Quite possibly the best design for a dryer vent
My previous dryer vent became useless after many years of use and the springs just gave up.  So I ordered this with the hope that a simpler design would mean a better implementation.

PROS
- Simple design
- Easy to clean

CONS
- Could be hard to install
- No mounting hardware included (!)

The biggest issue with this product is that it can be hard to install especially if you're replacing another vent.  In my case, I was concerned that the screw holes from the previous vent could interfere and prevent this vent from being secure on the house.  I got lucky but if things were shifted just 1/2 inch, I would have been in trouble.

On the installation, I'd recommend having some Good Stuff spray insulation and outdoor silicone caulk on hand.  When you take off the old dryer vent you will inevitable find that the original person who installed that vent did a poor job and there are large openings between the pipe and the house.  Make sure you fill in those voids since that can cause air leakage or allow insects to enter the house.

When you line up the product to install it, use a generous amount of caulk the surfaces mating with the house.  That will help make sure no water migrates into the house or the dryer pipe.  Also, make sure you have some mounting screws because inexplicably there are none included with the product (!).

The vent operates when air is being pushed out by the dryer.  When that happens, the plastic cover floats up and air is pushed out of the bottom of the vent.  Although I haven't used this long enough to clean it, it's pretty clear that this will be a cinch to clean.  There is a latch on the top that you have to unsnap and then the whole this is open to inspect and clean.

This one is a clear winner even if the installation is a little challenging.  But I'm sure other dryer vents would be a challenge to install as well.