As I was putting together my 140g peninsula style tank, rumor of a Red Sea peninsula started appearing. About the time I was putting water in my system, they were released. Neat system. A bit different from what I built, but not all that much, really. I am quite happy with my peninsula, but if that Red Sea had been available _before_ I built mine? Well, it'd have been tough not to go that way. Probably would have saved a bundle, too... over my completely custom setup.
If you have the room, and a peninsula system is what you're wanting... yeah, I'd say buy it.
On the other hand, I have found that 'settling' for something that isn't quite what you really want to save money is rarely a good buy. If you're going to end up unhappy with it, or end up buying twice, then it's likely a horrible decision.