FRER aren't as good as they used to be (I keep getting a shadow of a second line when it's BFN), but they're still the best I know of.

Like Tenibear, I use a combination of ICs (from inpregnancy on ebay) and FRER. I used the ICs to test out my trigger and booster shots during my last IUI cycle and they were still picking up a line the day before my BFN b/t (ie when my hcg levels were very low).