These are the four brands of solar heaters I have seen. The Solar Bear has 2" manifolds and the others have 1 1/2". Also, the Solar Bears consist of 4x20 one piece panels, while the others are 2x20 panels. Solar Bears cost more.
Are there any other differences?
The 4x20 panels would seem cleaner and easier to set up. However more expensive to replace if you could otherwise replace only a 2x20 panel in case of a leak, etc..
I live in Wisconsin so I will need to be able to move these indoors in winter. Are these easy to roll up without damaging them?