I bought my Truvativ stylos with an external bottom bracket for 110 off of Ebay...new.
External is just so much better than any other interface that I can't imagine riding any other crankset in a performance application.
While I've never snapped a square taper BB, I have worn out crankarms from wallowing out, and ISIS spindles, while noticeably stiffer than square taper , require a tiny cartridge ball bearing that doesn't take the abuse or have the longevity of a square taper BB.
External systems have spindles that are bigger/stiffer/lighter still, and have bottom bracket bearings that are more than twice as large as square taper BBs. To boot, you can remove and install crankarms for service as many times as you want, without a crank puller, without any damage to the interface of the cranks.
If 200 is your max budget, there are a ton of options for you to choose from.