The Kammer cages are very nice and I think if you went with one you would not be disappointed. If you are already using an 18x18x36 cage, the Forever cage will really not provide more space (it is actually smaller per square inch than the cage you currently have), so if space is what you want, go with the larger Panther Palace (or a standard 24x24x48. If you are not concerned about more space, but simply want a wider cage, go with the Forever. I would not worry about other members bashing you. Clearly you are doing your research and what you decide is ultimately best for you and your situation. Yes, vertical space is important to chameleons. You would probably not want a cage that is wider than it is tall, but I think that the "vertical space is the most important thing" mantra is not always correct. Panthers (and probably other species) defiantly benefit from lateral movement as I have seen. As long as your cage provides a decent amount of vertical space it is ok for it to be wider than the norm. One reason for vertical space is to provide areas of cooler temperature that your chameleon can retreat to when it is too hot. The Kammer cages will still provide enough vertical space to do this, but a cage like the Palace, that is wider will also provide these cooler areas along the width; you will be able to have one side of the cage warmer and the other side of the cage cooler.
I will eventually upgrade to the Palace because I really like what it offers, but while you are trying to decide, think about the following:
1. What do you have space for in your home?
2. Do you want to provide your chameleon with the most space you possibly can?
3. What cage can you afford? The Palace is not cheap and the standard 24x24x48 is typically more affordable.
4. Do you plan on keeping more than one or two chameleons in the future? People who keep several chams typically go for the taller 24x24x48 cages as they are more space efficient when setting up a row of cages along a wall. If you are only keeping one cham, a wider cage is nicer for display of the animal.
Regarding the Easy Drip system, I do not have this, but I thought it was really cool when Ed showed it to me. It won't work for my current setup because I do not hang my plants and the pots would be too heavy for the screen bottom to support. I may consider it though when I upgrade my cage.