Has anyone switched from clomid to femara

MC

And on cycle day 10 I got my first LG surge..I know ur not supposed to keep testing after that but i did today and it's even darker then yesterday even tho yesterday was my first positive.. I've been told femara gives false positives,however I always hit a surge on day 12 and I have so much EWCM which tells me it was a false positive. Does anyone have any feedback or experiences with femara?