Originally Posted by WhyFi

What I ended up doing, though - Powertap C1 chainrings. As of Mar 1st, Powertap/Saris is only selling them direct, but they bumped the price from $699 down to $349. This is a total power solution (with estimated L/R output, should you want that) for a very reasonable price, as long as your crankset is compatible (5-arm, 110 BCD without hidden bolts). My crankset wasn't compatible, but I tracked down an older Shimano crankset for less than $100 to pair with the Powertap. Do I like it? I don't know, I haven't received it yet - should be here tomorrow, I think.