Beauty is in the eye of the beholder. If you really wanna spend $175, then hell ya its worth it. For me personally, I wouldn't use it only cause of the cost and the amount of cars I do, but do a search and you'll see the results of people who have. I generally use Black Fire "Fire over Ice" set up. Its Wet diamond sealant and then the wax. I get dripping wet and stunning results with that.
If your starting from scratch and building up your supplies, I would stick with one brand. I know that BF has polishes that work on cermicoats and finish down well. Menzerna is a wonderful polish and I use it all the time. PF203 is my favorite "all around" polish only because it cuts and finishes down really well. I might follow that up with either P106 or p085rd, it really depends on what the customer is paying me to do. On my personal cars, I would do the PF203 and p085rd in a heartbeat.
The thing with BMW paint is, once you correct you, you wanna keep it looking great. A wax or sealant will accomplish that but with Opti-coat, your getting more protection and with proper washing rituals, you'll have less of a chance of causing swirls. Its perminate, but the the finished product looks amazing and it makes keeping it clean super easy. I also coat BMW wheels all the time with Opti Coat. It keeps the brake dust down and makes them REALLY easy to clean. As I'm sure you know since you have a BMW, those wheels get dirty quick and can get ruined if you don't stay on top of them!
Sorry for the long post. Hope that helps a little bit. Feel free to hit me up if you have any questions or need help in any way. And remember, HAVE FUN or else it becomes a lot like work.