IMHO, I agree with a few folks that it depends on where you live/drive to make this insurance bet pay out (or at least even out).
I have been rolling on 17" low profile tires since about 1995 on my old school Eclipse GSX (250,000 SoCal miles) and have only been disabled by nails twice (Then again i have AAA and they just flat bed my car home). I have four 10" subs in my hatch... so i have no spare tire. This car has only been using normal tires it's entire life. When I relocated here to the NJ area with brand new tires, I got a chipped rim on a NY pothole 2 months after i arrived here (less then 500 miles driven in NJ/NY) had to repair the rim and get a new tire. After that... I just don't drive my eclipse since March 2008 (current mileage on the car is 250,6xx miles).
I got my CPO 335xi in Jan '11 hit a pothole just seconds after paying at a toll booth (1.5 months after purchasing the car), the front tire blew out from the side and I had 2 bent rims. I wish I did get the insurance, because in 5 years time i think i can get the pay out back with low profile tires. I ended up getting a new set of 4 tires from Tirerack for $800 and had to fix the bent rims $300 (BMW offered me the T&W insurance for $1200, but i declined).
I actually do wish I could get a spare tire kit for the 335xi and switch to non-RFT's, because I strongly feel that the hard sidewalls on RFT's contribute to more bent rims. Also I feel that RFT's are prone to more failures (bubbles, bursts, nails shouldn't be patched, etc...). But since this is a daily driver for my wife now that she got her drivers license... I would rather just keep the safety of the RFT's.
If I were to do it again, I would ask more details on the T&W insurance, like: What is the deductible per issue?
Is there a $ limit or quantity limit on coverage expenses over the 5 years?
At what tread depth do they consider the tire not covered for replacement?
Under what conditions do they replace the wheel?
Under what conditions do the not replace a wheel (acceptable wear/damage)?
My wheels would balance after the pothole hit but when you spin the wheel... you can see it's wobbling on the inside. Also at freeway speeds you can feel a vibration inside. I'm not sure if BMW would cover that???
It would actually be nice if BMW would allow people to buy the wheel and tire insurance even after you drive off the lot or give you a cool off period where you can change your mind and cancel the insurance for a full refund.
Depending on the cost of the T&W insurance in the future, if I am getting something with a Tire Aspect Ratio of 45 or less here in the North East States (or any area that it snows or doesn't care about local roads)... then I think the bet is worth while because I won't have to worry about having to track down a tire deal, get it shipped to me, find it in stock, pay for mounting balancing, etc... I just drive to my nearest dealership and say "fix it".
To be honest, I actually wish they would come up with an insurance plan which you can pay for year-by-year and choose to re-new on an annual basis. I think the adoption rate on the insurance would be much higher at time of purchase and the cost annually would be a lot cheaper. I would be more hesitant to pay $1500 up front for 5 years, but more willing to pay $300 and try it out. The one other factor no one said anything about is... what if my car is totaled in the 5 year period?? can I cancel the insurance and get my prorated money back?