I tested with both Equate and First Response at both 11 & 12 dpo. Equate gave a MUCH clearer line. I wasn't happy with FR at all...the line was *hardly* there....like a shadow that you're referring to.
Here was my FR (squint hard and you can see a shadow )
And here was my equate on the same day...much easier to see.
I wasn't happy with First Response either - I took one on Monday evening (10 DPO) with the hintest faintest pink line ever....an hour later later (after driving to CVS in a state of total confusion) I used an EPT Certainty (digital), and it was positive - highly recommend the digital!