I've just bought a Fluval for my planted tank. We were looking for a bow fronted tank and the Fluval seemed good value. It has an external filter, whereas Juwel are internal taking up space. The only other issue that I worried about was lighting - Juwel lighting was higher wattage for the same size tank, but all other brands were much the same.
In the end I think you're choosing the quality of the build, the more you spend the better it should be. But they're all much same as regards the features you need for your aquarium
Regards
Keith