i use both the CBFM and the cheap ovulation test strips from saveontests.com.
over these past couple of years i have found that i am not getting any high days, only low fertility and peak fertility readings. i assume this means that as my hormones are getting more out of whack with age that i'm not registering on the monitor. in fact, last year i got a BFP/miscarriage when the CBFM didn't even give me a peak fertility reading. if i had been only relying on it, i might have missed the surge. i like to use both to keep the bases covered. plus, with the strips you can test in the late morning and the evening, making sure you don't miss the surge. i also have been recording my BBT to confirm ovulation and i find using all three methods keeps me busy, but also keeps me with a pretty good idea about what is going on with my cycles.